{"paper_id":"2eb159ab-85b3-4127-b4c7-c3f55ad3c0ac","body_text":"Impact of Labor Induction at 39 Weeks Gestation Compared with Expectant Management on Maternal and Perinatal Morbidity among a Cohort of Low-risk Women | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Impact of Labor Induction at 39 Weeks Gestation Compared with Expectant Management on Maternal and Perinatal Morbidity among a Cohort of Low-risk Women Sabrina C. Burn, Ruofan Yao, Maria Diaz, Jordan Rossi, Stephen Contag This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-289350/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 28 Dec, 2021 Read the published version in The Journal of Maternal-Fetal & Neonatal Medicine → Version 1 posted You are reading this latest preprint version Abstract Objective: To determine rates of maternal and perinatal outcomes after induction of labor (IOL) at 39 weeks compared with expectant management. Methods : Cohort study of low risk women delivered between 39-42 weeks from 2015 to 2018. We excluded births with fetal abnormalities, previous cesarean, multiple pregnancies or those with spontaneous onset of labor (SOL) or indicated delivery at 39 weeks. Data was abstracted from National Center for Health Statistics birth files. Relative risks (aRR) were estimated with multivariable log-binomial regression. Main Outcome Measures : Maternal outcomes: chorioamnionitis (Triple I), blood transfusion, neonatal intensive care unit (NICU) admission, uterine rupture, cesarean delivery and cesarean hysterectomy. Fetal and infant outcomes: fetal death, 5-minute Apgar ≤3, prolonged ventilation, seizures, ICU admission, and death within 28 days. Results: There were 15,900,956 births, with 8,540,063 after exclusions. The IOL group included 1,177,790 births excluding women with diabetes or hypertensive disease. There were 3,835,185 births after 39 weeks excluding women with diabetes or chronic hypertension. With IOL at 39 weeks the risk for blood transfusion (p-value < 0.01; aRR 0.78; 95% CI [0.75-0.82]), Triple I (p-value < 0.01; aRR 0.71; 95% CI [0.70-0.73]) and cesarean delivery (p-value <0.01; aRR 0.87; 95% CI [0.87-0.88]) were lower, albeit increased risk of cesarean hysterectomy (p-value <0.01; aRR 1.23; 95% CI [1.07-1.41]). Neonates had a lower risk for 5-minute Apgar ≤3 (p-value < 0.01; aRR 0.68; 95% CI [0.66-0.71]), prolonged ventilation (p-value < 0.01; aRR 0.84; 95% CI [0.81-0.87]), NICU admission (p-value < 0.01; aRR 0.86; 95% CI [0.85-0.87]), and neonatal seizures (p-value <0.01; aRR 0.85; 95% CI [0.76-0.96]). There was no difference in risk for neonatal death 0.99% (p-value 0.99; aRR 1.00; 95%CI [0.99-1.00]), or fetal death (p-value 0.78; aRR 1.0002; 95%CI [0.99-1.002]. This benefit was greater compared with each subsequent week. Conclusions: Induction of labor at 39 weeks of gestation in a low risk cohort is associated a lower risk of cesarean delivery, transfusions and infection, as well as lower neonatal morbidity, without difference in fetal or neonatal death. This appears to be associated with increased risk for cesarean hysterectomy. Maternal & Fetal Medicine induction of labor (IOL) maternal and perinatal outcomes Relative risks (aRR) spontaneous onset of labor (SOL) Figures Figure 1 Introduction Decisions regarding the timing for induction of labor (IOL) take into consideration both maternal and perinatal risks. Retrospective cohort studies have reported an increase in the frequency of cesarean deliveries associated with IOL when comparing women undergoing IOL with women having spontaneous onset of labor (SOL) at term 1 , 2 . Subsequent observational and retrospective cohort studies found that women who underwent IOL prior to 41 weeks of gestation had an increased frequency of operative vaginal deliveries and an increased risk for adverse neonatal outcomes and neonatal intensive care (NICU) admissions 3 – 8 . These led to recommendations to avoid elective IOL among low risk women and traditionally expectant management was seen as an effective strategy to decrease cesarean delivery rates in the population. Subsequent retrospective cohort studies reported longer a duration of labor but similar cesarean delivery and adverse neonatal outcome rates among nulliparous women with a favorable cervix undergoing elective IOL compared with those managed expectantly 9 . A larger population based cohort study reported decreased perinatal mortality with increased rates of admission to NICU without differences in cesarean delivery rates after term elective IOL in an unselected population 10 . Data from the National Center for Health Statistics (NCHS) from 2005 reported improved neonatal outcomes with a decrease in cesarean delivery rates among low risk nulliparous women having IOL at 39 weeks compared with expectant management 11 . This was also observed in a subsequent population based study using data from the State of California from 2006 that compared IOL among non-anomalous singleton pregnancies with expectant management for each week of gestation between 37 and 42 weeks. That study found the risk for cesarean delivery and adverse neonatal outcomes was decreased with IOL compared with expectant management. Prior to 39 weeks, there was an increased rate of neonatal hyperbilirubinemia 12 . There have been several meta-analyses of randomized controlled trials (RCT) reporting that IOL at term was associated with lower cesarean delivery rates as well as an improvement in neonatal outcomes, which is significant among term and post term pregnancies, but not among preterm deliveries 13 – 16 . All of these meta-analyses included women with singleton pregnancies undergoing IOL at 39 weeks but did not always specify the presence of maternal comorbidities or parity. Only one of these reported on a significant reduction on fetal death rate but did not specify whether maternal comorbidities were present 13 . The most recent meta-analyses included nulliparous low risk women and reported a reduction in cesarean delivery, perinatal mortality and morbidity with IOL at 39 weeks, compared with expectant management 14 . In the most recent meta-analysis, the overall findings were consistent with previous reports that show a clear reduction in cesarean deliveries, perinatal morbidity and mortality with a policy of labor induction at or beyond 37 weeks compared with expectant management. It also raised questions regarding risk profiles, whether IOL at 39 weeks is better than elective IOL at 40 or 41 weeks and recommends further research into women’s values and preferences. No evidence for adverse effects were found for a policy of elective induction in any of these studies 15 . The meta-analyses performed after 2018 reported similar results but were heavily influenced by the ARRIVE trial supporting elective IOL at 39 weeks for low risk nulliparous women 16 – 18 . These findings have led to a formal statement from the Society of Maternal Fetal Medicine stating that it is reasonable to offer elective IOL to low risk nulliparous women at 39 weeks 0 days of gestation or beyond, although further research is still required 19 . The impact of a policy of IOL at 39 weeks with a decrease in cesarean delivery rates supports this practice within a cohort of low risk nulliparous women with a singleton pregnancy. This policy excludes women with preexisting conditions or comorbidities such as prior cesarean delivery, where recent evidence showed that elective IOL among women with one prior cesarean delivery had improved neonatal outcomes but increased cesarean delivery rates 20 . The results from the Walker et al. and the ARRIVE trial, do not provide definitive evidence of potential advantages or disadvantages of labor induction at 39 weeks versus expectant management outside of a clinical trial 17 , 21 . Yet these recommendations are presumably adopted in a broad variety of clinical settings. It is with these previously published findings in mind, that we designed the current population based retrospective cohort study that includes all clinical settings, and which analyzed a low risk birth cohort delivered prior to the publication of the ARRIVE trial 17 . Our hypothesis is that IOL in a contemporary low risk cohort at 39 weeks, outside of a clinical research setting, is associated with a decreased rate of cesarean deliveries and improvement in perinatal outcomes compared with women managed expectantly up to 42 weeks. Methods This is a national retrospective cohort analysis using data abstracted from the NCHS and Centers for Disease Control and Prevention’s (CDC) Division of Vital Statistics database from 2015 to 2018 22 . We chose the most recent 4 years of livebirth and fetal death data available. These years reflect outcomes prior to the formal recommendations regarding elective IOL at 39 weeks 19 . The data is publicly available and de-identified, therefore institutional review board approval was not required. The intervention group consisted of all women undergoing IOL at 39 weeks of gestation without an identifiable medical indication, irrespective of their final mode of delivery. The expectant management group consisted of women delivered between 40 and 42 weeks of gestation. Weeks were stated as completed weeks of gestation, which is how this variable is reported in the fetal death or live birth databases. We excluded all women at less than 39 weeks or greater than 42 weeks of gestation, multifetal gestations, known fetal congenital anomalies or aneuploidy, with previous cesarean delivery, and infant deaths at greater than 28 days. These were excluded from analysis because of their association with postnatal complications often unrelated to the birth process 23 , 24 . Deliveries > 42 weeks gestation were excluded primarily because it is no longer common practice to continue expectant management at this gestational age given the inherent neonatal morbidities associated with post-date delivery 25 , 26 . Women with any form of diabetes or hypertension were excluded from the intervention group to isolate the effects of induction of labor at 39 weeks in a low risk cohort compared with expectant management in an otherwise low-risk population. These conditions are considered high-risk conditions with delivery recommended by 39 weeks 23 – 26 . Gestational hypertensive disorders can present after 39 weeks but were excluded if diagnosed in the 39th week, as delivery is recommended by 37 weeks or at time of diagnosis 24 . As such, expectant management would not be a reasonable option if the diagnosis was made in the 39th week, but would have been an option had they been diagnosed after 39 weeks, which is possible due to its incidence with advancing gestational age 17 , 27 . The fetal death database was merged with the livebirth database. There are variables that are included in the livebirth but not in the fetal death certificates. These include fetal congenital anomalies or aneuploidies, maternal puerperal infection, blood transfusion and cesarean hysterectomy. No imputations were performed and their absence is expected to produce an underestimate in the incidence of those outcomes. We included all fetal deaths from 40 to 42 weeks, but only intrapartum at 39 weeks 22 . We were able to identify this group by verifying when the diagnosis was made, whether it was pre-labor, intrapartum, or unknown. This variable is reported in all except for the following jurisdictions: District of Columbia, Hawaii, Kansas, Missouri, Montana, Nevada, and New York. Maternal demographic information was compared between the two management groups using the appropriate univariate statistical test. The maternal outcomes of interest included: cesarean delivery, intra-amniotic infection or inflammation (triple I), blood transfusion, intensive care unit (ICU) admission, uterine rupture, and cesarean hysterectomy. Triple I, or chorioamnionitis as it was previously known. The neonatal outcomes of interest included: fetal death, 5-minute Apgar score ≤ 3, assisted ventilation for > 6 hours, NICU admission, seizure, and neonatal death < 28 days of life. Multivariable log-binomial regression analysis was performed to calculate adjusted relative risk (aRR) to control for potential confounding variables based on historic significance and univariate analysis. These variables had to be included in both the certificate of live birth and fetal death and included maternal age, race, parity, education, prenatal care, cigarette use, and body mass index (BMI). Backward stepwise elimination method was performed to arrive at the final regression model, which included maternal education, ethnicity, parity, BMI and cigarette use. A secondary analysis reported frequencies for cesarean delivery, fetal and neonatal death, and seizures, in addition to calculating the relative risk for each subsequent week. We chose to calculate the relative risk (RR), which is usually the parameter of interest in cohort studies especially since odds ratios can overestimate risk for more common outcomes and overestimation of the importance of a risk factor may lead to intervention errors 28 . Statistical significance was defined as p-value < 0.01. Power analysis was not performed as the sample size included the entire population. All analyses were performed using Stata 14 statistical software (College Station, TX) 28 and we adhered to “Strengthening the Reporting of Observational Studies” (STROBE) guidelines for reporting cohort studies 29 . Results After exclusions, there were 5,017,524 births with 5,012,975 livebirths, 2,179 livebirths followed by neonatal death and 2,370 fetal deaths available for review. There were 1,177,790 low risk, singleton women, without a history of cesarean delivery, with non-anomalous pregnancies in the 39-week IOL or intervention group. This included 520 cases with neonatal death and 120 intrapartum fetal deaths. Among those managed expectantly, there were 3,835,185 births, of which there were 1,659 subsequent neonatal deaths, and 2,250 fetal deaths (Fig. 1 ). Maternal descriptive characteristics were similar between the two groups and summarized in Table 1 . In both groups, the mean maternal age was 28.0 years; the most common ethnicity among women was White followed by Black; the majority had a high school or greater level of education and the mean body mass index (BMI) was 26 kg/m2 in both groups with approximately 5 % of women reported as morbidly obese. Median parity was one in the IOL and zero in the expectantly managed group. Approximately one third of women in the IOL and over half of the women in the expectantly managed group had a prior vaginal delivery. Table 1 Maternal descriptive information for the low risk intervention group and the expectant management group Variable IOL at 39 weeks Expectant Management Age Maternal age (mean, s.d.) 28.2 (5.9) 28.1 (5.6) Advanced maternal age (n, %) 199,666 (16.9) 582,545 (15.2) Race White (n, %) 942,786 (80.0) 2,998,521 (78.1) Black (n, %) 167,077 (14.2) 540,296 (14.1) Hispanic (n, %) 11,678 (1.0) 38,724 (1.0) Other (n, %) 56889 (4.8) 261,553 (6.8) Education High school diploma (n, %) 307,971 (26.1) 895,059 (23.3) College or greater (n, %) 703,569 (59.7) 2,391,901 (62.3) High school incomplete (n, %) 166,890 (14.2) 552,134 (14.4) BMI BMI (mean, s.d.) 26.8 (6.5) 26.1 (6.0) BMI 30-39.9 kg/m2 (n, %) 247,102 (21.0) 688,343 (17.9) BMI ≥ 40 kg/m2 (n, %) 69,400 (5.9) 216,136 (5.6) Tobacco in pregnancy (n, %) 108,881 (9.2) 232,824 (6.1) Parity (median, IQR) 1 [0–2] 0 [0–1] Previous vaginal birth (n, %) 415,323 (35.2) 2,038,975 (53.1) s.d.: standard deviation IQR: Interquartile range n = number Approximately 35% of women managed expectantly underwent IOL for various indications while 65% had SOL. We observed an incidence of gestational hypertensive disease of 3% after 39 weeks. The relative risk for maternal morbidity was calculated by comparing the risk of IOL at 39 weeks to the using the risk for those managed expectantly as the reference value. The relative risks were adjusted for maternal education, ethnicity, parity, BMI and cigarette use. Women were significantly less likely to be diagnosed with any of the maternal outcomes analyzed after elective IOL at 39 weeks when compared to the expectant management group (Table 2 ). Although there was no difference in uterine rupture rate, or ICU admission between groups, the risk for a cesarean hysterectomy was unexpectedly increased in the IOL group. The most common adverse outcomes for the entire cohort were cesarean delivery and Triple I. The rate of cesarean delivery in the elective IOL group was 13% lower than in the expectantly managed group after adjusted analysis. Elective IOL at 39 weeks was also associated with a 30% reduction in risk for puerperal infection compared with expectant management after risk adjustment. Table 2 Maternal outcomes for induction of labor at 39 weeks compared with expectant management Outcomes Induction of labor at 39 weeks Expectant management (reference group) Relative risk N (%) N (%) Unadjusted Adjusted a 95% CI P-value Cesarean delivery 145,974 (12.39) 686,103 (17.87) 0.69 0.87 0.87–0.88 < 0.01 Blood transfusion 3,155 (0.27) 10,780 (0.28) 0.72 0.78 0.75–0.82 < 0.01 Triple I 15,072 (1.28) 93,633 (2.44) 0.52 0.71 0.70–0.73 < 0.01 ICU admission 837 (0.07) 2,866 (0.07) 0.95 1.03 0.95–1.12 0.44 Uterine rupture 164 (0.01) 441 (0.01) 1.21 1.12 0.94–1.35 0.21 C-hysterectomy 299 (0.03) 745 (0.02) 1.31 1.23 1.07–1.41 < 0.01 a: Adjusted for maternal education greater less than high school, minority race, nulliparous status, body mass index less than 18 or greater than 25 kg /m2 or smoking in the second and third trimesters. ICU: Intensive care unit Triple I: Intrauterine infection or inflammation C-hysterectomy: cesarean hysterectomy Fetal and neonatal morbidity and mortality were evaluated by comparing the risk among those managed expectantly with infants delivered after elective IOL at 39 weeks using the expectantly managed cases as the reference (Table 3 ). Neonates in the IOL group were 30% less likely to have 5 min Apgar ≤ 3, over 15% less likely to require prolonged, necessitate NICU admission, or neonatal seizures when compared with the expectant management group. There was no difference in the frequency or relative risk of neonatal or fetal death between the two groups (P-value 0.04). When we compared the frequency and relative risk at each week of gestation compared with the risk of elective IOL at 39 weeks, we found a gradual increase from 40 to 42 weeks in the risk for cesarean delivery as well as for neonatal seizures, but no difference in the risk for fetal or neonatal death (Table 4 ). Table 3 Neonatal outcomes for induction of labor at 39 weeks compared with expectant management Outcomes Induction of labor at 39 weeks Expectant management (reference group) Relative risk N (%) N (%) Unadjusted Adjusted a 95% CI P-value Fetal death 120 (0.01) 2,250 (0.06) 1.0005 1.0002 0.99–1.002 0.78 5 min Apgar ≤ 3 2,456 (0.21) 11,793(0.31) 0.60 0.68 0.66–0.71 < 0.01 Prolonged ventilation 3,438 (0.30) 15,586 (0.41) 0.73 0.84 0.81–0.87 < 0.01 NICU 33,401 (2.90) 148,391 (3.89) 0.74 0.86 0.85–0.87 < 0.01 Seizure 296 (0.03) 1,344 (0.04) 0.73 0.85 0.75–0.96 < 0.01 Neonatal death 520 (0.04) 1,659 (0.04) 1.02 1.00 0.99-1.00 0.99 a: Adjusted for maternal education greater less than high school, minority race, nulliparous status, body mass index less than 18 or greater than 25 kg /m2 or smoking in the second and third trimesters. NICU: Neonatal intensive care unit Table 4 Severe maternal and neonatal outcomes at each week from 39 to 40 weeks with the relative risk for severe maternal and neonatal outcomes at each week compared with induction of labor at 39 weeks. Outcomes 39 weeks 40 weeks 41 weeks 42 weeks N (%) N (%) aRR a (95%CI) N (%) aRR a (95%CI) N (%) aRR a (95%CI) Fetal death 120 (0.01) 1,660 (0.06) 1.00 (0.99–1.003) 500 (0.05) 1.00 (0.99 to 1.004) 90 (0.20) 1.00 (0.98 to 1.01) Seizure 296 (0.03) 880 (0.03) 1.11 (0.85 to 1.45) 421 (0.05) 2.08 (1.54 to 2.83) 14 (0.07) 9.56 (5.01 to 18.22) Neonatal death 520 (0.04) 1,160 (0.04) 1.00 (0.99 to 1.003) 434 (0.05) 1.00 (0.99 to 1.004) 43 (0.10) 1.00 (1.00 to 1.00) Cesarean delivery 145,974 (12.39) 471,469 (16.35) 1.17 (1.16 to 1.19) 203,689 (22.35) 1.70 (1.67 to 1.72 10,945 (24.48) 2.28 (2.19 to 2.37) a: Adjusted for maternal education greater less than high school, minority race, nulliparous status, body mass index less than 18 or greater than 25 kg /m2 or smoking in the second and third trimesters. Discussion Main Findings This retrospective study analyzed data from a cohort of singleton, non-anomalous pregnancies among low-risk women who were delivered within various health care settings across the United States, prior statements published by large national organizations supporting elective IOL at 39 weeks 19 . Our data demonstrated a 13% reduction in risk for cesarean delivery, and a 30% reduction in the risk for chorioamnionitis among women who underwent induction of labor at 39 weeks of gestation compared with women managed expectantly past 39 weeks. This small to moderate protective effect was also seen for blood transfusion, cesarean hysterectomy, and ICU admission. The large National institute of Health (NIH) funded RCT regarding elective induction of labor at 39 weeks included a very specific population of low risk nulliparous women 17 . Although ours is a retrospective cohort study, it reflects a large national cohort analyzed over the course of 4 years prior to the publication of the trial results. The population included was not limited to low risk nulliparous women being delivered at large academic medical centers under a strict trial protocol, but considered all low risk women including multiparas being delivered at centers providing different levels of care under different standards and with presumed differences regarding elective IOL at term. Our finding of a decreased rate of cesarean delivery and blood transfusion is consistent with a decreased risk for postpartum hemorrhage, puerperal infection, and uterine rupture, all risk factors for cesarean hysterectomy and ICU admission in the puerperium. This is important as previous work reported in the literature not only raised concerns with IOL at term and increased risk for cesarean delivery, but also reported complications directly related to the process of IOL 30 , 31 . Multiple studies have reported an increased risk for uterine rupture associated with cervical ripening agents and IOL but this is after a prior cesarean delivery 32 . Our finding of lower risk for transfusion in the IOL group is reassuring but regrettably provides a limited assessment of the amount of blood loss at delivery and frequency of postpartum hemorrhage as this is not a variable reported in the live or stillbirth certificate. The data also does not allow us to gauge the severity of the intrapartum hemorrhage or the volume of blood transfused. A novel finding of our study is the 23% increase of the rate of cesarean hysterectomy in the induction of labor group. This new finding was identified as the large study population is powered to detect rare adverse outcomes. The increased rate of cesarean hysterectomy cannot be attributed to differences in the rates of uterine rupture or obstetrical hemorrhage, the two most common indications, as these were either not different or lower within the IOL group. Induction agents, such as prostaglandins and oxytocin, have also been associated with risk for uterine atony and rupture; however, we were unable to determine what agents were used for IOL 30 – 34 . Due to the nature of this study, the indication for cesarean hysterectomy could not be determined in this cohort, however, the overall rate was lower (0.01%) than recent rates reported with induction of labor among nulliparous women undergoing IOL (0.11%) and history of cesarean delivery 33 . Factors associated with risk for cesarean hysterectomy include high parity, maternal age, previous cesarean delivery, placental pathology, uterine atony and uterine rupture 34 . We have demonstrated that the risk for cesarean and transfusion was lower in the IOL group, and although parity was higher in the IOL group, it also included a higher proportion of nulliparous women. Any effect from BMI was controlled for in the multivariate regression analysis. Although cause for uterine rupture is multifactorial, the factors that led to the increased risk will require future analysis, especially for factors that we were unable to analyze, including methods used for cervical ripening and induction of labor, duration of labor, and indications for cesarean delivery. From a fetal and neonatal perspective, our data demonstrated that IOL at 39 weeks of gestation resulted in a significantly lower frequency of 5-minute Apgar ≤ 3, requirement for ventilation, seizures or NICU admission compared with the expectant management group. Additionally, expectant management was not associated with an increase in the risk of fetal or neonatal deaths up to 28 days after delivery even when comparing progressively later weeks to 39 weeks. This is in contrast to what was seen with neonatal seizures and cesarean delivery, which had progressively higher rates and relative risks with each additional week of gestation. Strengths & Limitations The strength of the current study is the heterogeneous nature and large sample size of pregnancies analyzed in both the elective IOL at 39 weeks of gestation group and the expectant management group. It was important to include fetal deaths that occurred during IOL of labor at 39 weeks in order to compare with the risk for fetal death with expectant management. We were able to do this by using the variable that is included in the certificate of fetal death describing the timing at which the death occurred although not reported consistently for all jurisdictions. Underreporting of intrapartum deaths would lead to a lower estimate of risk in the IOL group and overestimation of risk in the expectantly managed group where all fetal deaths are counted. An additional strength of this study is the quality of the data. The data collected and analyzed is based on birth certificate and fetal death certificate data. Although the quality of the data especially that related to gestational age has been questioned, the current use of the best obstetrical estimate of gestational age has validated this as a reliable variable 35 . We were also able to adjust the relative risks and include clinically relevant confounders. Limitations of this study include the inability to review the indications for induction of labor, methods utilized for induction of labor, Bishop score, fetal monitoring, severity of bleeding requiring transfusion, severity of uterine rupture versus dehiscence, and/or indications for intervention such as cesarean delivery. However, it is assumed there is enough similarity in practice recommended by the American College of Obstetrics and Gynecology that this would not directly affect the data collected. Previous evaluation of the validity of this data supports it as reliable with a high degree of completeness and accuracy 29 . Interpretation The decision to proceed with elective induction of labor at 39 weeks is highly dependent on several factors among which the most important are adequate dating and calculation of the estimated date of delivery. In settings where this is not reliably determined, planning IOL can be associated with complications related to late preterm and early term delivery 36 . Dating relies on the last menstrual period and first trimester ultrasound 36 . When discrepancies occur ultrasound dating is used with varying degrees of uncertainty depending on the gestational age at which it is performed 36 . Implementing a standardized strategy for IOL is indispensable to avoid complications that have been reported in association with injudicious use of oxytocin or other cervical ripening agent 37 , 38 . The majority of IOL procedures occur in a hospital setting requiring adequate infrastructure and healthcare provider support to be performed safely 38 . After initiating IOL, fetal surveillance is an imperative, and standardized interpretation and response to abnormal fetal heart rate patterns are needed to avoid unnecessary interventions and the increased cesarean delivery rates reported in earlier studies 37 – 39 . Currently approximately 25% of pregnancies undergo elective IOL at various gestational ages 38 . As the majority of pregnancies deliver at a modal gestational age of 39 weeks, elective IOL would not necessarily be required for all women, but a standard of care emphasizing IOL at 39 weeks would lead to a significant increase of these procedures with their associated costs related to the interventions listed above 40 – 43 . Furthermore, it is concerning that resources allocated to IOL would decrease those available to care for high risk women as well as for those having a SOL. This concern may be misleading because they compare IOL to SOL 14 . The observed decrease in the cesarean section rates and improved perinatal outcomes would most likely be associated with decreased short and long-term costs. Even if short-term costs were similar, the improved perinatal outcomes would justify the intervention 40 – 43 . Our findings are consistent with the most recently published studies and meta-analysis regarding elective induction of labor at 39 weeks gestation versus expectant management included women of advanced maternal age in one study and nulliparous women in the recent randomized controlled trial 11 , 15 , 17 – 19 , 42 , 44 , 45 . Primary outcomes in these reports include cesarean delivery rates as well as composite neonatal outcome. Their results indicated that induction of labor at 39 weeks did not result in an increased rate of cesarean delivery and reported no increase in the rate of adverse neonatal outcomes. Conclusions In conclusion, our study demonstrates that in low-risk women induction of labor at 39 weeks gestation is benefits maternal or neonatal outcomes with significantly lower frequencies of maternal and neonatal morbidity when compared to expectant management through 42 weeks. We have also shown in secondary analysis that the risk for both maternal and fetal complications increases with each additional week of gestation after 39 weeks. Based on our study and supported by a growing body of literature, clinical protocols aimed at the avoidance of IOL at 39 weeks gestation in low-risk women seems unwarranted. Discussions should address the significant improvement in maternal and perinatal outcomes. The finding of increased rate of cesarean hysterectomy should be further investigated, particularly those factors that may potentially contribute to this complication. Abbreviations IOL: Induction of labor SOL: Spontaneous onset of labor Triple I: Chorioamnionitis NICU: Neonatal intensive care unit aRR: Adjusted relative risk RR: Relative risk RCT : Randomized controlled trial NIH: National Institutes of Health NCHS: National Center for Health Statistics CDC: Center for Disease Control and Prevention BMI: Body mass index STROBE: Strengthening the Reporting of Observational Studies Declarations Ethics approval and consent to participate: This study is a national retrospective cohort analysis using data abstracted from the NCHS and CDC’s Division of Vital Statistics database. The data is publicly available and de-identified; therefore, no patients were directly involved and no ethics board approval was required. Consent for publication: All contributing authors provided consent for publication. Availability of data and material: All data is publicly available from the webpage of the National Center for Health Statistics, a division of the CDC, and can be downloaded from https://www.cdc.gov/nchs/data_access/vitalstatsonline.htm Disclosures of interests: No conflicts of interest to declare. Funding: No funding was required or requested to carry out this research Contribution to Authorship: SC and RY planned the study and obtained the necessary data. All authors (SCB, RY, MD, JR, SC) contributed to the analysis of the data and interpretation of results. SCB drafted the manuscript and all other authors assisted with editing of the manuscript. All authors have accepted it in its final form. Acknowledgements: We would like to thank the National Center for Health Statistics (NCHS) and Centers for Disease Control and Prevention’s (CDC) Division of Vital Statistics for the creation and maintenance of this freely accessible database. Disclosure The author(s) report no conflict of interest References Macer JA, Macer CL, Chan LS. Elective induction versus spontaneous labor: a retrospective study of complications and outcome. American journal of obstetrics and gynecology. 1992;166(6 Pt 1):1690-1696; discussion 1696-1697. Maslow AS, Sweeny AL. Elective induction of labor as a risk factor for cesarean delivery among low-risk women at term. Obstet Gynecol. 2000;95(6 Pt 1):917-922. Cammu H, Martens G, Ruyssinck G, Amy JJ. Outcome after elective labor induction in nulliparous women: a matched cohort study. American journal of obstetrics and gynecology. 2002;186(2):240-244. Dunne C, Da Silva O, Schmidt G, Natale R. Outcomes of elective labour induction and elective caesarean section in low-risk pregnancies between 37 and 41 weeks' gestation. J Obstet Gynaecol Can. 2009;31(12):1124-1130. Ehrenthal DB, Jiang X, Strobino DM. Labor induction and the risk of a cesarean delivery among nulliparous women at term. 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Cheng YW, Kaimal AJ, Snowden JM, Nicholson JM, Caughey AB. Induction of labor compared to expectant management in low-risk women and associated perinatal outcomes. American journal of obstetrics and gynecology. 2012;207(6):502.e501-508. Darney BG, Snowden JM, Cheng YW, et al. Elective induction of labor at term compared with expectant management: maternal and neonatal outcomes. Obstet Gynecol. 2013;122(4):761-769. Mishanina E, Rogozinska E, Thatthi T, Uddin-Khan R, Khan KS, Meads C. Use of labour induction and risk of cesarean delivery: a systematic review and meta-analysis. CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne. 2014;186(9):665-673. Grobman WA, Caughey AB. Elective induction of labor at 39 weeks compared with expectant management: a meta-analysis of cohort studies. American journal of obstetrics and gynecology. 2019;221(4):304-310. Middleton P, Shepherd E, Morris J, Crowther CA, Gomersall JC. Induction of labour at or beyond 37 weeks' gestation. Cochrane Database Syst Rev. 2020;7(7):Cd004945. Saccone G, Della Corte L, Maruotti GM, et al. Induction of labor at full-term in pregnant women with uncomplicated singleton pregnancy: A systematic review and meta-analysis of randomized trials. Acta obstetricia et gynecologica Scandinavica. 2019;98(8):958-966. Grobman WA, Rice MM, Reddy UM, et al. Labor Induction versus Expectant Management in Low-Risk Nulliparous Women. The New England journal of medicine. 2018;379(6):513-523. Sotiriadis A, Petousis S, Thilaganathan B, et al. Maternal and perinatal outcomes after elective induction of labor at 39 weeks in uncomplicated singleton pregnancy: a meta-analysis. Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology. 2019;53(1):26-35. Society of Maternal Fetal Medicine. SMFM Statement on Elective Induction of Labor in Low-Risk Nulliparous Women at Term: the ARRIVE Trial. American journal of obstetrics and gynecology. 2019;221(1):B2-b4. Park BY, Cryer A, Betoni J, et al. Outcomes of labor induction at 39 weeks in pregnancies with a prior cesarean delivery. The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstet. 2020:1-6. Walker KF, Bugg GJ, Macpherson M, et al. Randomized Trial of Labor Induction in Women 35 Years of Age or Older. The New England journal of medicine. 2016;374(9):813-822. National Center for Health Statistics. 2021. https://www.cdc.gov/nchs/data_access/vitalstatsonline.htm. Accessed 02/02/2021. American College of Obstetrics and Gynecology. ACOG Practice Bulletin No. 203: Chronic Hypertension in Pregnancy. Obstet Gynecol. 2019;133(1):e26-e50. American College of Obstetricians and Gynecologists. Gestational Hypertension and Preeclampsia: ACOG Practice Bulletin, Number 222. Obstet Gynecol. 2020;135(6):e237-e260. American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 201: Pregestational Diabetes Mellitus. Obstet Gynecol. 2018;132(6):e228-e248. American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 190: Gestational Diabetes Mellitus. Obstet Gynecol. 2018;131(2):e49-e64. Elsmén E, Källén K, Marsál K, Hellström-Westas L. Fetal gender and gestational-age-related incidence of pre-eclampsia. Acta obstetricia et gynecologica Scandinavica. 2006;85(11):1285-1291. McNutt LA, Wu C, Xue X, Hafner JP. Estimating the relative risk in cohort studies and clinical trials of common outcomes. American journal of epidemiology. 2003;157(10):940-943. von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke JP. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: guidelines for reporting observational studies. International journal of surgery (London, England). 2014;12(12):1495-1499. Thisted DL, Mortensen LH, Krebs L. Uterine rupture without previous caesarean delivery: a population-based cohort study. European journal of obstetrics, gynecology, and reproductive biology. 2015;195:151-155. Rydahl E, Eriksen L, Juhl M. Effects of induction of labor prior to post-term in low-risk pregnancies: a systematic review. JBI database of systematic reviews and implementation reports. 2019;17(2):170-208. Lydon-Rochelle M, Holt VL, Easterling TR, Martin DP. Risk of uterine rupture during labor among women with a prior cesarean delivery. The New England journal of medicine. 2001;345(1):3-8. Sørbye IK, Oppegaard KS, Weeks A, Marsdal K, Jacobsen AF. Induction of labor and nulliparity: A nationwide clinical practice pilot evaluation. Acta obstetricia et gynecologica Scandinavica. 2020;99(12):1700-1709. van den Akker T, Brobbel C, Dekkers OM, Bloemenkamp KWM. Prevalence, Indications, Risk Indicators, and Outcomes of Emergency Peripartum Hysterectomy Worldwide: A Systematic Review and Meta-analysis. Obstet Gynecol. 2016;128(6):1281-1294. Martin JA, Hamilton BE, Osterman MJK, Driscoll AK. Births: Final Data for 2018. National vital statistics reports : from the Centers for Disease Control and Prevention, National Center for Health Statistics, National Vital Statistics System. 2019;68(13):1-47. American College of Obstetricians and Gynecologists. Committee Opinion No 700: Methods for Estimating the Due Date. Obstet Gynecol. 2017;129(5):e150-e154. Kernberg A, Caughey AB. Augmentation of Labor: A Review of Oxytocin Augmentation and Active Management of Labor. Obstetrics and gynecology clinics of North America. 2017;44(4):593-600. Tsakiridis I, Mamopoulos A, Athanasiadis A, Dagklis T. Induction of Labor: An Overview of Guidelines. Obstetrical & gynecological survey. 2020;75(1):61-72. Association of Women’s Health OaNN. Elective Induction of Labor. Nursing for women's health. 2019;23(2):177-179. Little SE. Elective Induction of Labor: What is the Impact? Obstetrics and gynecology clinics of North America. 2017;44(4):601-614. Hersh AR, Skeith AE, Sargent JA, Caughey AB. Induction of labor at 39 weeks of gestation versus expectant management for low-risk nulliparous women: a cost-effectiveness analysis. American journal of obstetrics and gynecology. 2019;220(6):590.e591-590.e510. Einerson BD, Nelson RE, Sandoval G, et al. Cost of Elective Labor Induction Compared With Expectant Management in Nulliparous Women. Obstet Gynecol. 2020;136(1):19-25. Caughey AB, Sundaram V, Kaimal AJ, et al. Maternal and neonatal outcomes of elective induction of labor. Evidence report/technology assessment. 2009(176):1-257. Souter V, Painter I, Sitcov K, Caughey AB. Maternal and newborn outcomes with elective induction of labor at term. American journal of obstetrics and gynecology. 2019;220(3):273.e271-273.e211. Walker KF, Bugg G, Macpherson M, et al. Induction of labour versus expectant management for nulliparous women over 35 years of age: a multi-centre prospective, randomised controlled trial. BMC pregnancy and childbirth. 2012;12:145. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 28 Dec, 2021 Read the published version in The Journal of Maternal-Fetal & Neonatal Medicine → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {\"props\":{\"pageProps\":{\"initialData\":{\"identity\":\"rs-289350\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":true,\"archivedVersions\":[],\"articleType\":\"Research Article\",\"associatedPublications\":[],\"authors\":[{\"id\":15091262,\"identity\":\"f6565a93-0ce7-4b98-8012-d5b1c96b9e7d\",\"order_by\":0,\"name\":\"Sabrina C. Burn\",\"email\":\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAjklEQVRIiWNgGAWjYBACAxDxAYlNnBbGGSRrYeYhSYu5RO6zx7Zt2/IY2Ju3SRClxXJGurlxbtvtYgaeY2XEaTG4kcYmDdSS2CCRY0aCFkuQFvk3pGhhBNvCQ6QWy55nbJI9524ntvGkFVsQpcWcPY1N4kfZ7cR+9sMbbxClBQ7YSFM+CkbBKBgFowAvAAAi/SjOCCViqgAAAABJRU5ErkJggg==\",\"orcid\":\"\",\"institution\":\"University of Minnesota\",\"correspondingAuthor\":true,\"prefix\":\"\",\"firstName\":\"Sabrina\",\"middleName\":\"C.\",\"lastName\":\"Burn\",\"suffix\":\"\"},{\"id\":15091263,\"identity\":\"d890772d-8933-4636-a20e-576b34e0ee4f\",\"order_by\":1,\"name\":\"Ruofan Yao\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Loma Linda University School of Medicine\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Ruofan\",\"middleName\":\"\",\"lastName\":\"Yao\",\"suffix\":\"\"},{\"id\":15091264,\"identity\":\"3e65fd78-27c1-4706-b817-0ec55b5f75ca\",\"order_by\":2,\"name\":\"Maria Diaz\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Loma Linda University School of Medicine\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Maria\",\"middleName\":\"\",\"lastName\":\"Diaz\",\"suffix\":\"\"},{\"id\":15091265,\"identity\":\"e2fdc6bc-32b6-4c71-9e03-80d88c17b26c\",\"order_by\":3,\"name\":\"Jordan Rossi\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Loma Linda University School of Medicine\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Jordan\",\"middleName\":\"\",\"lastName\":\"Rossi\",\"suffix\":\"\"},{\"id\":15091266,\"identity\":\"f82b1ac6-744a-4462-b96c-76399c507de2\",\"order_by\":4,\"name\":\"Stephen Contag\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"University of Minnesota\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Stephen\",\"middleName\":\"\",\"lastName\":\"Contag\",\"suffix\":\"\"}],\"badges\":[],\"createdAt\":\"2021-03-01 16:14:12\",\"currentVersionCode\":1,\"declarations\":\"\",\"doi\":\"10.21203/rs.3.rs-289350/v1\",\"doiUrl\":\"https://doi.org/10.21203/rs.3.rs-289350/v1\",\"draftVersion\":[],\"editorialEvents\":[{\"content\":\"https://doi.org/10.1080/14767058.2021.2021396\",\"type\":\"published\",\"date\":\"2021-12-29T02:43:44+00:00\"}],\"editorialNote\":\"\",\"failedWorkflow\":false,\"files\":[{\"id\":6982339,\"identity\":\"197ae6f4-7d90-4614-999d-e32774737aec\",\"added_by\":\"auto\",\"created_at\":\"2021-03-15 20:25:49\",\"extension\":\"png\",\"order_by\":1,\"title\":\"Figure 1\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":118453,\"visible\":true,\"origin\":\"\",\"legend\":\"Flow diagram of the cohort selection from births and fetal deaths reported from 2015 to 2018\\n\\n\",\"description\":\"\",\"filename\":\"floatimage1.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-289350/v1/209a07515b1a73753f0241e2.png\"},{\"id\":16854942,\"identity\":\"6ca11145-bdbb-43ff-b209-58672feee11f\",\"added_by\":\"auto\",\"created_at\":\"2021-12-30 02:43:51\",\"extension\":\"pdf\",\"order_by\":0,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"manuscript-pdf\",\"size\":592487,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"manuscript.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-289350/v1/6dc4c699-5032-4d5b-8982-ebd39718b39b.pdf\"}],\"financialInterests\":\"No competing interests reported.\",\"formattedTitle\":\"\\u003cp\\u003eImpact of Labor Induction at 39 Weeks Gestation Compared with Expectant Management on Maternal and Perinatal Morbidity among a Cohort of Low-risk Women\\u003c/p\\u003e\",\"fulltext\":[{\"header\":\"Introduction\",\"content\":\" \\u003cp\\u003eDecisions regarding the timing for induction of labor (IOL) take into consideration both maternal and perinatal risks. Retrospective cohort studies have reported an increase in the frequency of cesarean deliveries associated with IOL when comparing women undergoing IOL with women having spontaneous onset of labor (SOL) at term \\u003csup\\u003e\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e\\u003c/sup\\u003e. Subsequent observational and retrospective cohort studies found that women who underwent IOL prior to 41 weeks of gestation had an increased frequency of operative vaginal deliveries and an increased risk for adverse neonatal outcomes and neonatal intensive care (NICU) admissions \\u003csup\\u003e\\u003cspan additionalcitationids=\\\"CR4 CR5 CR6 CR7\\\" citationid=\\\"CR3\\\" class=\\\"CitationRef\\\"\\u003e3\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR8\\\" class=\\\"CitationRef\\\"\\u003e8\\u003c/span\\u003e\\u003c/sup\\u003e. These led to recommendations to avoid elective IOL among low risk women and traditionally expectant management was seen as an effective strategy to decrease cesarean delivery rates in the population.\\u003c/p\\u003e \\u003cp\\u003eSubsequent retrospective cohort studies reported longer a duration of labor but similar cesarean delivery and adverse neonatal outcome rates among nulliparous women with a favorable cervix undergoing elective IOL compared with those managed expectantly \\u003csup\\u003e\\u003cspan citationid=\\\"CR9\\\" class=\\\"CitationRef\\\"\\u003e9\\u003c/span\\u003e\\u003c/sup\\u003e. A larger population based cohort study reported decreased perinatal mortality with increased rates of admission to NICU without differences in cesarean delivery rates after term elective IOL in an unselected population \\u003csup\\u003e\\u003cspan citationid=\\\"CR10\\\" class=\\\"CitationRef\\\"\\u003e10\\u003c/span\\u003e\\u003c/sup\\u003e. Data from the National Center for Health Statistics (NCHS) from 2005 reported improved neonatal outcomes with a decrease in cesarean delivery rates among low risk nulliparous women having IOL at 39 weeks compared with expectant management \\u003csup\\u003e\\u003cspan citationid=\\\"CR11\\\" class=\\\"CitationRef\\\"\\u003e11\\u003c/span\\u003e\\u003c/sup\\u003e. This was also observed in a subsequent population based study using data from the State of California from 2006 that compared IOL among non-anomalous singleton pregnancies with expectant management for each week of gestation between 37 and 42 weeks. That study found the risk for cesarean delivery and adverse neonatal outcomes was decreased with IOL compared with expectant management. Prior to 39 weeks, there was an increased rate of neonatal hyperbilirubinemia \\u003csup\\u003e\\u003cspan citationid=\\\"CR12\\\" class=\\\"CitationRef\\\"\\u003e12\\u003c/span\\u003e\\u003c/sup\\u003e. There have been several meta-analyses of randomized controlled trials (RCT) reporting that IOL at term was associated with lower cesarean delivery rates as well as an improvement in neonatal outcomes, which is significant among term and post term pregnancies, but not among preterm deliveries \\u003csup\\u003e\\u003cspan additionalcitationids=\\\"CR14 CR15\\\" citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u003c/sup\\u003e. All of these meta-analyses included women with singleton pregnancies undergoing IOL at 39 weeks but did not always specify the presence of maternal comorbidities or parity. Only one of these reported on a significant reduction on fetal death rate but did not specify whether maternal comorbidities were present \\u003csup\\u003e\\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e\\u003c/sup\\u003e. The most recent meta-analyses included nulliparous low risk women and reported a reduction in cesarean delivery, perinatal mortality and morbidity with IOL at 39 weeks, compared with expectant management \\u003csup\\u003e\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e\\u003c/sup\\u003e. In the most recent meta-analysis, the overall findings were consistent with previous reports that show a clear reduction in cesarean deliveries, perinatal morbidity and mortality with a policy of labor induction at or beyond 37 weeks compared with expectant management. It also raised questions regarding risk profiles, whether IOL at 39 weeks is better than elective IOL at 40 or 41 weeks and recommends further research into women\\u0026rsquo;s values and preferences. No evidence for adverse effects were found for a policy of elective induction in any of these studies \\u003csup\\u003e\\u003cspan citationid=\\\"CR15\\\" class=\\\"CitationRef\\\"\\u003e15\\u003c/span\\u003e\\u003c/sup\\u003e.\\u003c/p\\u003e \\u003cp\\u003eThe meta-analyses performed after 2018 reported similar results but were heavily influenced by the ARRIVE trial supporting elective IOL at 39 weeks for low risk nulliparous women \\u003csup\\u003e\\u003cspan additionalcitationids=\\\"CR17\\\" citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR18\\\" class=\\\"CitationRef\\\"\\u003e18\\u003c/span\\u003e\\u003c/sup\\u003e. These findings have led to a formal statement from the Society of Maternal Fetal Medicine stating that it is reasonable to offer elective IOL to low risk nulliparous women at 39 weeks 0 days of gestation or beyond, although further research is still required \\u003csup\\u003e\\u003cspan citationid=\\\"CR19\\\" class=\\\"CitationRef\\\"\\u003e19\\u003c/span\\u003e\\u003c/sup\\u003e. The impact of a policy of IOL at 39 weeks with a decrease in cesarean delivery rates supports this practice within a cohort of low risk nulliparous women with a singleton pregnancy. This policy excludes women with preexisting conditions or comorbidities such as prior cesarean delivery, where recent evidence showed that elective IOL among women with one prior cesarean delivery had improved neonatal outcomes but increased cesarean delivery rates \\u003csup\\u003e\\u003cspan citationid=\\\"CR20\\\" class=\\\"CitationRef\\\"\\u003e20\\u003c/span\\u003e\\u003c/sup\\u003e.\\u003c/p\\u003e \\u003cp\\u003eThe results from the Walker et al. and the ARRIVE trial, do not provide definitive evidence of potential advantages or disadvantages of labor induction at 39 weeks versus expectant management outside of a clinical trial \\u003csup\\u003e\\u003cspan citationid=\\\"CR17\\\" class=\\\"CitationRef\\\"\\u003e17\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e\\u003c/sup\\u003e. Yet these recommendations are presumably adopted in a broad variety of clinical settings.\\u003c/p\\u003e \\u003cp\\u003eIt is with these previously published findings in mind, that we designed the current population based retrospective cohort study that includes all clinical settings, and which analyzed a low risk birth cohort delivered prior to the publication of the ARRIVE trial \\u003csup\\u003e\\u003cspan citationid=\\\"CR17\\\" class=\\\"CitationRef\\\"\\u003e17\\u003c/span\\u003e\\u003c/sup\\u003e. Our hypothesis is that IOL in a contemporary low risk cohort at 39 weeks, outside of a clinical research setting, is associated with a decreased rate of cesarean deliveries and improvement in perinatal outcomes compared with women managed expectantly up to 42 weeks.\\u003c/p\\u003e \"},{\"header\":\"Methods\",\"content\":\"\\u003cp\\u003eThis is a national retrospective cohort analysis using data abstracted from the NCHS and Centers for Disease Control and Prevention\\u0026rsquo;s (CDC) Division of Vital Statistics database from 2015 to 2018 \\u003csup\\u003e22\\u003c/sup\\u003e. We chose the most recent 4 years of livebirth and fetal death data available. These years reflect outcomes prior to the formal recommendations regarding elective IOL at 39 weeks \\u003csup\\u003e\\u003cspan citationid=\\\"CR19\\\" class=\\\"CitationRef\\\"\\u003e19\\u003c/span\\u003e\\u003c/sup\\u003e. The data is publicly available and de-identified, therefore institutional review board approval was not required.\\u003c/p\\u003e\\u003cp\\u003eThe intervention group consisted of all women undergoing IOL at 39 weeks of gestation without an identifiable medical indication, irrespective of their final mode of delivery. The expectant management group consisted of women delivered between 40 and 42 weeks of gestation. Weeks were stated as completed weeks of gestation, which is how this variable is reported in the fetal death or live birth databases.\\u003c/p\\u003e\\u003cp\\u003eWe excluded all women at less than 39 weeks or greater than 42 weeks of gestation, multifetal gestations, known fetal congenital anomalies or aneuploidy, with previous cesarean delivery, and infant deaths at greater than 28 days. These were excluded from analysis because of their association with postnatal complications often unrelated to the birth process \\u003csup\\u003e\\u003cspan citationid=\\\"CR23\\\" class=\\\"CitationRef\\\"\\u003e23\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR24\\\" class=\\\"CitationRef\\\"\\u003e24\\u003c/span\\u003e\\u003c/sup\\u003e. Deliveries\\u0026thinsp;\\u0026gt;\\u0026thinsp;42 weeks gestation were excluded primarily because it is no longer common practice to continue expectant management at this gestational age given the inherent neonatal morbidities associated with post-date delivery \\u003csup\\u003e\\u003cspan citationid=\\\"CR25\\\" class=\\\"CitationRef\\\"\\u003e25\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR26\\\" class=\\\"CitationRef\\\"\\u003e26\\u003c/span\\u003e\\u003c/sup\\u003e. Women with any form of diabetes or hypertension were excluded from the intervention group to isolate the effects of induction of labor at 39 weeks in a low risk cohort compared with expectant management in an otherwise low-risk population. These conditions are considered high-risk conditions with delivery recommended by 39 weeks \\u003csup\\u003e\\u003cspan additionalcitationids=\\\"CR24 CR25\\\" citationid=\\\"CR23\\\" class=\\\"CitationRef\\\"\\u003e23\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR26\\\" class=\\\"CitationRef\\\"\\u003e26\\u003c/span\\u003e\\u003c/sup\\u003e. Gestational hypertensive disorders can present after 39 weeks but were excluded if diagnosed in the 39th week, as delivery is recommended by 37 weeks or at time of diagnosis \\u003csup\\u003e\\u003cspan citationid=\\\"CR24\\\" class=\\\"CitationRef\\\"\\u003e24\\u003c/span\\u003e\\u003c/sup\\u003e. As such, expectant management would not be a reasonable option if the diagnosis was made in the 39th week, but would have been an option had they been diagnosed after 39 weeks, which is possible due to its incidence with advancing gestational age \\u003csup\\u003e\\u003cspan citationid=\\\"CR17\\\" class=\\\"CitationRef\\\"\\u003e17\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR27\\\" class=\\\"CitationRef\\\"\\u003e27\\u003c/span\\u003e\\u003c/sup\\u003e.\\u003c/p\\u003e\\u003cp\\u003eThe fetal death database was merged with the livebirth database. There are variables that are included in the livebirth but not in the fetal death certificates. These include fetal congenital anomalies or aneuploidies, maternal puerperal infection, blood transfusion and cesarean hysterectomy. No imputations were performed and their absence is expected to produce an underestimate in the incidence of those outcomes.\\u003c/p\\u003e\\u003cp\\u003eWe included all fetal deaths from 40 to 42 weeks, but only intrapartum at 39 weeks \\u003csup\\u003e\\u003cspan citationid=\\\"CR22\\\" class=\\\"CitationRef\\\"\\u003e22\\u003c/span\\u003e\\u003c/sup\\u003e. We were able to identify this group by verifying when the diagnosis was made, whether it was pre-labor, intrapartum, or unknown. This variable is reported in all except for the following jurisdictions: District of Columbia, Hawaii, Kansas, Missouri, Montana, Nevada, and New York.\\u003c/p\\u003e\\u003cp\\u003eMaternal demographic information was compared between the two management groups using the appropriate univariate statistical test. The maternal outcomes of interest included: cesarean delivery, intra-amniotic infection or inflammation (triple I), blood transfusion, intensive care unit (ICU) admission, uterine rupture, and cesarean hysterectomy. Triple I, or chorioamnionitis as it was previously known. The neonatal outcomes of interest included: fetal death, 5-minute Apgar score\\u0026thinsp;\\u0026le;\\u0026thinsp;3, assisted ventilation for \\u0026gt;\\u0026thinsp;6 hours, NICU admission, seizure, and neonatal death\\u0026thinsp;\\u0026lt;\\u0026thinsp;28 days of life.\\u003c/p\\u003e\\u003cp\\u003eMultivariable log-binomial regression analysis was performed to calculate adjusted relative risk (aRR) to control for potential confounding variables based on historic significance and univariate analysis. These variables had to be included in both the certificate of live birth and fetal death and included maternal age, race, parity, education, prenatal care, cigarette use, and body mass index (BMI). Backward stepwise elimination method was performed to arrive at the final regression model, which included maternal education, ethnicity, parity, BMI and cigarette use. A secondary analysis reported frequencies for cesarean delivery, fetal and neonatal death, and seizures, in addition to calculating the relative risk for each subsequent week.\\u003c/p\\u003e\\u003cp\\u003eWe chose to calculate the relative risk (RR), which is usually the parameter of interest in cohort studies especially since odds ratios can overestimate risk for more common outcomes and overestimation of the importance of a risk factor may lead to intervention errors \\u003csup\\u003e\\u003cspan citationid=\\\"CR28\\\" class=\\\"CitationRef\\\"\\u003e28\\u003c/span\\u003e\\u003c/sup\\u003e. Statistical significance was defined as p-value\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.01. Power analysis was not performed as the sample size included the entire population. All analyses were performed using Stata 14 statistical software (College Station, TX) \\u003csup\\u003e\\u003cspan citationid=\\\"CR28\\\" class=\\\"CitationRef\\\"\\u003e28\\u003c/span\\u003e\\u003c/sup\\u003e and we adhered to \\u0026ldquo;Strengthening the Reporting of Observational Studies\\u0026rdquo; (STROBE) guidelines for reporting cohort studies \\u003csup\\u003e\\u003cspan citationid=\\\"CR29\\\" class=\\\"CitationRef\\\"\\u003e29\\u003c/span\\u003e\\u003c/sup\\u003e.\\u003c/p\\u003e\"},{\"header\":\"Results\",\"content\":\" \\u003cp\\u003eAfter exclusions, there were 5,017,524 births with 5,012,975 livebirths, 2,179 livebirths followed by neonatal death and 2,370 fetal deaths available for review. There were 1,177,790 low risk, singleton women, without a history of cesarean delivery, with non-anomalous pregnancies in the 39-week IOL or intervention group. This included 520 cases with neonatal death and 120 intrapartum fetal deaths. Among those managed expectantly, there were 3,835,185 births, of which there were 1,659 subsequent neonatal deaths, and 2,250 fetal deaths (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e).\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e \\u003cp\\u003eMaternal descriptive characteristics were similar between the two groups and summarized in Table\\u0026nbsp;\\u003cspan refid=\\\"Tab1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e. In both groups, the mean maternal age was 28.0 years; the most common ethnicity among women was White followed by Black; the majority had a high school or greater level of education and the mean body mass index (BMI) was 26 kg/m2 in both groups with approximately 5 % of women reported as morbidly obese. Median parity was one in the IOL and zero in the expectantly managed group. Approximately one third of women in the IOL and over half of the women in the expectantly managed group had a prior vaginal delivery.\\u003c/p\\u003e \\u003cp\\u003e \\u003cdiv class=\\\"gridtable\\\"\\u003e\\u003ctable float=\\\"Yes\\\" id=\\\"Tab1\\\" border=\\\"1\\\"\\u003e \\u003ccaption language=\\\"En\\\"\\u003e \\u003cdiv class=\\\"CaptionNumber\\\"\\u003eTable 1\\u003c/div\\u003e \\u003cdiv class=\\\"CaptionContent\\\"\\u003e \\u003cp\\u003eMaternal descriptive information for the low risk intervention group and the expectant management group\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/caption\\u003e \\u003ccolgroup cols=\\\"3\\\"\\u003e \\u003cthead\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eVariable\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eIOL at 39 weeks\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eExpectant Management\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003c/thead\\u003e \\u003ctbody\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colspan=\\\"3\\\" nameend=\\\"c3\\\" namest=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eAge\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eMaternal age (mean, s.d.)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e28.2 (5.9)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e28.1 (5.6)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eAdvanced maternal age (n, %)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e199,666 (16.9)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e582,545 (15.2)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colspan=\\\"3\\\" nameend=\\\"c3\\\" namest=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eRace\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eWhite (n, %)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e942,786 (80.0)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e2,998,521 (78.1)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eBlack (n, %)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e167,077 (14.2)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e540,296 (14.1)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eHispanic (n, %)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e11,678 (1.0)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e38,724 (1.0)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eOther (n, %)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e56889 (4.8)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e261,553 (6.8)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colspan=\\\"3\\\" nameend=\\\"c3\\\" namest=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eEducation\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eHigh school diploma (n, %)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e307,971 (26.1)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e895,059 (23.3)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eCollege or greater (n, %)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e703,569 (59.7)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e2,391,901 (62.3)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eHigh school incomplete (n, %)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e166,890 (14.2)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e552,134 (14.4)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colspan=\\\"3\\\" nameend=\\\"c3\\\" namest=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eBMI\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eBMI (mean, s.d.)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e26.8 (6.5)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e26.1 (6.0)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eBMI 30-39.9 kg/m2 (n, %)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e247,102 (21.0)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e688,343 (17.9)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eBMI\\u0026thinsp;\\u0026ge;\\u0026thinsp;40 kg/m2 (n, %)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e69,400 (5.9)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e216,136 (5.6)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eTobacco in pregnancy (n, %)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e108,881 (9.2)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e232,824 (6.1)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003eParity (median, IQR)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e1 [0\\u0026ndash;2]\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e0 [0\\u0026ndash;1]\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003ePrevious vaginal birth (n, %)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e415,323 (35.2)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e2,038,975 (53.1)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colspan=\\\"3\\\" nameend=\\\"c3\\\" namest=\\\"c1\\\"\\u003e \\u003cp\\u003es.d.: standard deviation\\u003c/p\\u003e \\u003cp\\u003eIQR: Interquartile range\\u003c/p\\u003e \\u003cp\\u003en\\u0026thinsp;=\\u0026thinsp;number\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003c/tbody\\u003e \\u003c/colgroup\\u003e \\u003c/table\\u003e\\u003c/div\\u003e \\u003c/p\\u003e \\u003cp\\u003eApproximately 35% of women managed expectantly underwent IOL for various indications while 65% had SOL. We observed an incidence of gestational hypertensive disease of 3% after 39 weeks. The relative risk for maternal morbidity was calculated by comparing the risk of IOL at 39 weeks to the using the risk for those managed expectantly as the reference value. The relative risks were adjusted for maternal education, ethnicity, parity, BMI and cigarette use. Women were significantly less likely to be diagnosed with any of the maternal outcomes analyzed after elective IOL at 39 weeks when compared to the expectant management group (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e). Although there was no difference in uterine rupture rate, or ICU admission between groups, the risk for a cesarean hysterectomy was unexpectedly increased in the IOL group. The most common adverse outcomes for the entire cohort were cesarean delivery and Triple I. The rate of cesarean delivery in the elective IOL group was 13% lower than in the expectantly managed group after adjusted analysis. Elective IOL at 39 weeks was also associated with a 30% reduction in risk for puerperal infection compared with expectant management after risk adjustment.\\u003c/p\\u003e \\u003cp\\u003e \\u003cdiv class=\\\"gridtable\\\"\\u003e\\u003ctable float=\\\"Yes\\\" id=\\\"Tab2\\\" border=\\\"1\\\"\\u003e \\u003ccaption language=\\\"En\\\"\\u003e \\u003cdiv class=\\\"CaptionNumber\\\"\\u003eTable 2\\u003c/div\\u003e \\u003cdiv class=\\\"CaptionContent\\\"\\u003e \\u003cp\\u003eMaternal outcomes for induction of labor at 39 weeks compared with expectant management\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/caption\\u003e \\u003ccolgroup cols=\\\"7\\\"\\u003e \\u003cthead\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c1\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003eOutcomes\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eInduction of labor at 39 weeks\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eExpectant\\u003c/p\\u003e \\u003cp\\u003emanagement\\u003c/p\\u003e \\u003cp\\u003e(reference group)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colspan=\\\"4\\\" nameend=\\\"c7\\\" namest=\\\"c4\\\"\\u003e \\u003cp\\u003eRelative risk\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eN (%)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eN (%)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eUnadjusted\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003eAdjusted \\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e95% CI\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003eP-value\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003c/thead\\u003e \\u003ctbody\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eCesarean delivery\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e145,974 (12.39)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e686,103 (17.87)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.69\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.87\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e0.87\\u0026ndash;0.88\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e\\u0026lt;\\u0026thinsp;0.01\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eBlood transfusion\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e3,155 (0.27)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e10,780 (0.28)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e\\u003cem\\u003e0.72\\u003c/em\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e\\u003cem\\u003e0.78\\u003c/em\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e\\u003cem\\u003e0.75\\u0026ndash;0.82\\u003c/em\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e\\u003cem\\u003e\\u0026lt;\\u0026thinsp;0.01\\u003c/em\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eTriple I\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e15,072 (1.28)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e93,633 (2.44)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.52\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.71\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e0.70\\u0026ndash;0.73\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e\\u0026lt;\\u0026thinsp;0.01\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eICU admission\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e837 (0.07)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e2,866 (0.07)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.95\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e1.03\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e0.95\\u0026ndash;1.12\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e0.44\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eUterine rupture\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e164 (0.01)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e441 (0.01)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1.21\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e1.12\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e0.94\\u0026ndash;1.35\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e0.21\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eC-hysterectomy\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e299 (0.03)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e745 (0.02)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1.31\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e1.23\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e1.07\\u0026ndash;1.41\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e\\u0026lt;\\u0026thinsp;0.01\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colspan=\\\"7\\\" nameend=\\\"c7\\\" namest=\\\"c1\\\"\\u003e \\u003cp\\u003ea: Adjusted for maternal education greater less than high school, minority race, nulliparous status, body mass index less than 18 or greater than 25 kg /m2 or smoking in the second and third trimesters.\\u003c/p\\u003e \\u003cp\\u003eICU: Intensive care unit\\u003c/p\\u003e \\u003cp\\u003eTriple I: Intrauterine infection or inflammation\\u003c/p\\u003e \\u003cp\\u003eC-hysterectomy: cesarean hysterectomy\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003c/tbody\\u003e \\u003c/colgroup\\u003e \\u003c/table\\u003e\\u003c/div\\u003e \\u003c/p\\u003e \\u003cp\\u003eFetal and neonatal morbidity and mortality were evaluated by comparing the risk among those managed expectantly with infants delivered after elective IOL at 39 weeks using the expectantly managed cases as the reference (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab3\\\" class=\\\"InternalRef\\\"\\u003e3\\u003c/span\\u003e). Neonates in the IOL group were 30% less likely to have 5 min Apgar\\u0026thinsp;\\u0026le;\\u0026thinsp;3, over 15% less likely to require prolonged, necessitate NICU admission, or neonatal seizures when compared with the expectant management group. There was no difference in the frequency or relative risk of neonatal or fetal death between the two groups (P-value 0.04). When we compared the frequency and relative risk at each week of gestation compared with the risk of elective IOL at 39 weeks, we found a gradual increase from 40 to 42 weeks in the risk for cesarean delivery as well as for neonatal seizures, but no difference in the risk for fetal or neonatal death (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab4\\\" class=\\\"InternalRef\\\"\\u003e4\\u003c/span\\u003e).\\u003c/p\\u003e \\u003cp\\u003e \\u003cdiv class=\\\"gridtable\\\"\\u003e\\u003ctable float=\\\"Yes\\\" id=\\\"Tab3\\\" border=\\\"1\\\"\\u003e \\u003ccaption language=\\\"En\\\"\\u003e \\u003cdiv class=\\\"CaptionNumber\\\"\\u003eTable 3\\u003c/div\\u003e \\u003cdiv class=\\\"CaptionContent\\\"\\u003e \\u003cp\\u003eNeonatal outcomes for induction of labor at 39 weeks compared with expectant management\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/caption\\u003e \\u003ccolgroup cols=\\\"7\\\"\\u003e \\u003cthead\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c1\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003eOutcomes\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eInduction of\\u003c/p\\u003e \\u003cp\\u003elabor at 39 weeks\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eExpectant\\u003c/p\\u003e \\u003cp\\u003emanagement\\u003c/p\\u003e \\u003cp\\u003e(reference group)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colspan=\\\"4\\\" nameend=\\\"c7\\\" namest=\\\"c4\\\"\\u003e \\u003cp\\u003eRelative risk\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eN (%)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eN (%)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eUnadjusted\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003eAdjusted \\u003csup\\u003ea\\u003c/sup\\u003e\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e95% CI\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003eP-value\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003c/thead\\u003e \\u003ctbody\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eFetal death\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e120 (0.01)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e2,250 (0.06)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1.0005\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e1.0002\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e0.99\\u0026ndash;1.002\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e0.78\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003e5 min\\u003c/b\\u003e\\u003c/p\\u003e \\u003cp\\u003e\\u003cb\\u003eApgar\\u0026thinsp;\\u0026le;\\u0026thinsp;3\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e2,456 (0.21)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e11,793(0.31)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.60\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e\\u003cem\\u003e0.68\\u003c/em\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e\\u003cem\\u003e0.66\\u0026ndash;0.71\\u003c/em\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e\\u003cem\\u003e\\u0026lt;\\u0026thinsp;0.01\\u003c/em\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eProlonged ventilation\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e3,438 (0.30)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e15,586 (0.41)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.73\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.84\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e0.81\\u0026ndash;0.87\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e\\u0026lt;\\u0026thinsp;0.01\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eNICU\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e33,401 (2.90)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e148,391 (3.89)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.74\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.86\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e0.85\\u0026ndash;0.87\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e\\u0026lt;\\u0026thinsp;0.01\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eSeizure\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e296 (0.03)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e1,344 (0.04)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e0.73\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e0.85\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e0.75\\u0026ndash;0.96\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e\\u0026lt;\\u0026thinsp;0.01\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eNeonatal death\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e520 (0.04)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e1,659 (0.04)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1.02\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e1.00\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e0.99-1.00\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e0.99\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colspan=\\\"7\\\" nameend=\\\"c7\\\" namest=\\\"c1\\\"\\u003e \\u003cp\\u003ea: Adjusted for maternal education greater less than high school, minority race, nulliparous status, body mass index less than 18 or greater than 25 kg /m2 or smoking in the second and third trimesters.\\u003c/p\\u003e \\u003cp\\u003eNICU: Neonatal intensive care unit\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003c/tbody\\u003e \\u003c/colgroup\\u003e \\u003c/table\\u003e\\u003c/div\\u003e \\u003c/p\\u003e \\u003cp\\u003e \\u003cdiv class=\\\"gridtable\\\"\\u003e\\u003ctable float=\\\"Yes\\\" id=\\\"Tab4\\\" border=\\\"1\\\"\\u003e \\u003ccaption language=\\\"En\\\"\\u003e \\u003cdiv class=\\\"CaptionNumber\\\"\\u003eTable 4\\u003c/div\\u003e \\u003cdiv class=\\\"CaptionContent\\\"\\u003e \\u003cp\\u003eSevere maternal and neonatal outcomes at each week from 39 to 40 weeks with the relative risk for severe maternal and neonatal outcomes at each week compared with induction of labor at 39 weeks.\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/caption\\u003e \\u003ccolgroup cols=\\\"8\\\"\\u003e \\u003cthead\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c1\\\" morerows=\\\"1\\\" rowspan=\\\"2\\\"\\u003e \\u003cp\\u003eOutcomes\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e39 weeks\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colspan=\\\"2\\\" nameend=\\\"c4\\\" namest=\\\"c3\\\"\\u003e \\u003cp\\u003e40 weeks\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colspan=\\\"2\\\" nameend=\\\"c6\\\" namest=\\\"c5\\\"\\u003e \\u003cp\\u003e41 weeks\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colspan=\\\"2\\\" nameend=\\\"c8\\\" namest=\\\"c7\\\"\\u003e \\u003cp\\u003e42 weeks\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eN (%)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eN (%)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eaRR\\u003csup\\u003ea\\u003c/sup\\u003e (95%CI)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003eN (%)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003eaRR\\u003csup\\u003ea\\u003c/sup\\u003e (95%CI)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003eN (%)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003eaRR\\u003csup\\u003ea\\u003c/sup\\u003e (95%CI)\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003c/thead\\u003e \\u003ctbody\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eFetal death\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e120 (0.01)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e1,660 (0.06)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1.00 (0.99\\u0026ndash;1.003)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e500 (0.05)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e1.00 (0.99 to 1.004)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e90 (0.20)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1.00 (0.98 to 1.01)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eSeizure\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e296 (0.03)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e880 (0.03)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1.11 (0.85 to 1.45)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e421 (0.05)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e2.08 (1.54 to 2.83)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e14 (0.07)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e9.56 (5.01 to 18.22)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eNeonatal death\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e520 (0.04)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e1,160 (0.04)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1.00 (0.99 to 1.003)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e434 (0.05)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e1.00 (0.99 to 1.004)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e43 (0.10)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1.00 (1.00 to 1.00)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e\\u003cb\\u003eCesarean delivery\\u003c/b\\u003e\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003e145,974 (12.39)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e471,469 (16.35)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e1.17 (1.16 to 1.19)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003e203,689 (22.35)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003e1.70 (1.67 to 1.72\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003e10,945 (24.48)\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e2.28 (2.19 to 2.37)\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colspan=\\\"8\\\" nameend=\\\"c8\\\" namest=\\\"c1\\\"\\u003e \\u003cp\\u003ea: Adjusted for maternal education greater less than high school, minority race, nulliparous status, body mass index less than 18 or greater than 25 kg /m2 or smoking in the second and third trimesters.\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003c/tbody\\u003e \\u003c/colgroup\\u003e \\u003c/table\\u003e\\u003c/div\\u003e \\u003c/p\\u003e \"},{\"header\":\"Discussion\",\"content\":\"\\u003cdiv id=\\\"Sec5\\\" class=\\\"Section2\\\"\\u003e\\u003ch2\\u003eMain Findings\\u003c/h2\\u003e\\u003cp\\u003eThis retrospective study analyzed data from a cohort of singleton, non-anomalous pregnancies among low-risk women who were delivered within various health care settings across the United States, prior statements published by large national organizations supporting elective IOL at 39 weeks \\u003csup\\u003e\\u003cspan citationid=\\\"CR19\\\" class=\\\"CitationRef\\\"\\u003e19\\u003c/span\\u003e\\u003c/sup\\u003e. Our data demonstrated a 13% reduction in risk for cesarean delivery, and a 30% reduction in the risk for chorioamnionitis among women who underwent induction of labor at 39 weeks of gestation compared with women managed expectantly past 39 weeks. This small to moderate protective effect was also seen for blood transfusion, cesarean hysterectomy, and ICU admission.\\u003c/p\\u003e\\u003cp\\u003eThe large National institute of Health (NIH) funded RCT regarding elective induction of labor at 39 weeks included a very specific population of low risk nulliparous women \\u003csup\\u003e\\u003cspan citationid=\\\"CR17\\\" class=\\\"CitationRef\\\"\\u003e17\\u003c/span\\u003e\\u003c/sup\\u003e. Although ours is a retrospective cohort study, it reflects a large national cohort analyzed over the course of 4 years prior to the publication of the trial results. The population included was not limited to low risk nulliparous women being delivered at large academic medical centers under a strict trial protocol, but considered all low risk women including multiparas being delivered at centers providing different levels of care under different standards and with presumed differences regarding elective IOL at term.\\u003c/p\\u003e\\u003cp\\u003eOur finding of a decreased rate of cesarean delivery and blood transfusion is consistent with a decreased risk for postpartum hemorrhage, puerperal infection, and uterine rupture, all risk factors for cesarean hysterectomy and ICU admission in the puerperium. This is important as previous work reported in the literature not only raised concerns with IOL at term and increased risk for cesarean delivery, but also reported complications directly related to the process of IOL \\u003csup\\u003e\\u003cspan citationid=\\\"CR30\\\" class=\\\"CitationRef\\\"\\u003e30\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR31\\\" class=\\\"CitationRef\\\"\\u003e31\\u003c/span\\u003e\\u003c/sup\\u003e. Multiple studies have reported an increased risk for uterine rupture associated with cervical ripening agents and IOL but this is after a prior cesarean delivery \\u003csup\\u003e\\u003cspan citationid=\\\"CR32\\\" class=\\\"CitationRef\\\"\\u003e32\\u003c/span\\u003e\\u003c/sup\\u003e.\\u003c/p\\u003e\\u003cp\\u003eOur finding of lower risk for transfusion in the IOL group is reassuring but regrettably provides a limited assessment of the amount of blood loss at delivery and frequency of postpartum hemorrhage as this is not a variable reported in the live or stillbirth certificate. The data also does not allow us to gauge the severity of the intrapartum hemorrhage or the volume of blood transfused.\\u003c/p\\u003e\\u003cp\\u003eA novel finding of our study is the 23% increase of the rate of cesarean hysterectomy in the induction of labor group. This new finding was identified as the large study population is powered to detect rare adverse outcomes. The increased rate of cesarean hysterectomy cannot be attributed to differences in the rates of uterine rupture or obstetrical hemorrhage, the two most common indications, as these were either not different or lower within the IOL group. Induction agents, such as prostaglandins and oxytocin, have also been associated with risk for uterine atony and rupture; however, we were unable to determine what agents were used for IOL \\u003csup\\u003e\\u003cspan additionalcitationids=\\\"CR31 CR32 CR33\\\" citationid=\\\"CR30\\\" class=\\\"CitationRef\\\"\\u003e30\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR34\\\" class=\\\"CitationRef\\\"\\u003e34\\u003c/span\\u003e\\u003c/sup\\u003e. Due to the nature of this study, the indication for cesarean hysterectomy could not be determined in this cohort, however, the overall rate was lower (0.01%) than recent rates reported with induction of labor among nulliparous women undergoing IOL (0.11%) and history of cesarean delivery \\u003csup\\u003e\\u003cspan citationid=\\\"CR33\\\" class=\\\"CitationRef\\\"\\u003e33\\u003c/span\\u003e\\u003c/sup\\u003e. Factors associated with risk for cesarean hysterectomy include high parity, maternal age, previous cesarean delivery, placental pathology, uterine atony and uterine rupture \\u003csup\\u003e\\u003cspan citationid=\\\"CR34\\\" class=\\\"CitationRef\\\"\\u003e34\\u003c/span\\u003e\\u003c/sup\\u003e. We have demonstrated that the risk for cesarean and transfusion was lower in the IOL group, and although parity was higher in the IOL group, it also included a higher proportion of nulliparous women. Any effect from BMI was controlled for in the multivariate regression analysis. Although cause for uterine rupture is multifactorial, the factors that led to the increased risk will require future analysis, especially for factors that we were unable to analyze, including methods used for cervical ripening and induction of labor, duration of labor, and indications for cesarean delivery.\\u003c/p\\u003e\\u003cp\\u003eFrom a fetal and neonatal perspective, our data demonstrated that IOL at 39 weeks of gestation resulted in a significantly lower frequency of 5-minute Apgar\\u0026thinsp;\\u0026le;\\u0026thinsp;3, requirement for ventilation, seizures or NICU admission compared with the expectant management group. Additionally, expectant management was not associated with an increase in the risk of fetal or neonatal deaths up to 28 days after delivery even when comparing progressively later weeks to 39 weeks. This is in contrast to what was seen with neonatal seizures and cesarean delivery, which had progressively higher rates and relative risks with each additional week of gestation.\\u003c/p\\u003e\\u003c/div\\u003e\\u003cdiv id=\\\"Sec6\\\" class=\\\"Section2\\\"\\u003e\\u003ch2\\u003eStrengths \\u0026amp; Limitations\\u003c/h2\\u003e\\u003cp\\u003eThe strength of the current study is the heterogeneous nature and large sample size of pregnancies analyzed in both the elective IOL at 39 weeks of gestation group and the expectant management group. It was important to include fetal deaths that occurred during IOL of labor at 39 weeks in order to compare with the risk for fetal death with expectant management. We were able to do this by using the variable that is included in the certificate of fetal death describing the timing at which the death occurred although not reported consistently for all jurisdictions. Underreporting of intrapartum deaths would lead to a lower estimate of risk in the IOL group and overestimation of risk in the expectantly managed group where all fetal deaths are counted. An additional strength of this study is the quality of the data. The data collected and analyzed is based on birth certificate and fetal death certificate data. Although the quality of the data especially that related to gestational age has been questioned, the current use of the best obstetrical estimate of gestational age has validated this as a reliable variable \\u003csup\\u003e\\u003cspan citationid=\\\"CR35\\\" class=\\\"CitationRef\\\"\\u003e35\\u003c/span\\u003e\\u003c/sup\\u003e. We were also able to adjust the relative risks and include clinically relevant confounders.\\u003c/p\\u003e\\u003cp\\u003eLimitations of this study include the inability to review the indications for induction of labor, methods utilized for induction of labor, Bishop score, fetal monitoring, severity of bleeding requiring transfusion, severity of uterine rupture versus dehiscence, and/or indications for intervention such as cesarean delivery. However, it is assumed there is enough similarity in practice recommended by the American College of Obstetrics and Gynecology that this would not directly affect the data collected. Previous evaluation of the validity of this data supports it as reliable with a high degree of completeness and accuracy \\u003csup\\u003e\\u003cspan citationid=\\\"CR29\\\" class=\\\"CitationRef\\\"\\u003e29\\u003c/span\\u003e\\u003c/sup\\u003e.\\u003c/p\\u003e\\u003c/div\\u003e\\u003cdiv id=\\\"Sec7\\\" class=\\\"Section2\\\"\\u003e\\u003ch2\\u003eInterpretation\\u003c/h2\\u003e\\u003cp\\u003eThe decision to proceed with elective induction of labor at 39 weeks is highly dependent on several factors among which the most important are adequate dating and calculation of the estimated date of delivery. In settings where this is not reliably determined, planning IOL can be associated with complications related to late preterm and early term delivery \\u003csup\\u003e\\u003cspan citationid=\\\"CR36\\\" class=\\\"CitationRef\\\"\\u003e36\\u003c/span\\u003e\\u003c/sup\\u003e. Dating relies on the last menstrual period and first trimester ultrasound \\u003csup\\u003e\\u003cspan citationid=\\\"CR36\\\" class=\\\"CitationRef\\\"\\u003e36\\u003c/span\\u003e\\u003c/sup\\u003e. When discrepancies occur ultrasound dating is used with varying degrees of uncertainty depending on the gestational age at which it is performed \\u003csup\\u003e\\u003cspan citationid=\\\"CR36\\\" class=\\\"CitationRef\\\"\\u003e36\\u003c/span\\u003e\\u003c/sup\\u003e. Implementing a standardized strategy for IOL is indispensable to avoid complications that have been reported in association with injudicious use of oxytocin or other cervical ripening agent \\u003csup\\u003e\\u003cspan citationid=\\\"CR37\\\" class=\\\"CitationRef\\\"\\u003e37\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR38\\\" class=\\\"CitationRef\\\"\\u003e38\\u003c/span\\u003e\\u003c/sup\\u003e. The majority of IOL procedures occur in a hospital setting requiring adequate infrastructure and healthcare provider support to be performed safely \\u003csup\\u003e\\u003cspan citationid=\\\"CR38\\\" class=\\\"CitationRef\\\"\\u003e38\\u003c/span\\u003e\\u003c/sup\\u003e. After initiating IOL, fetal surveillance is an imperative, and standardized interpretation and response to abnormal fetal heart rate patterns are needed to avoid unnecessary interventions and the increased cesarean delivery rates reported in earlier studies\\u003csup\\u003e\\u003cspan additionalcitationids=\\\"CR38\\\" citationid=\\\"CR37\\\" class=\\\"CitationRef\\\"\\u003e37\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR39\\\" class=\\\"CitationRef\\\"\\u003e39\\u003c/span\\u003e\\u003c/sup\\u003e. Currently approximately 25% of pregnancies undergo elective IOL at various gestational ages \\u003csup\\u003e\\u003cspan citationid=\\\"CR38\\\" class=\\\"CitationRef\\\"\\u003e38\\u003c/span\\u003e\\u003c/sup\\u003e. As the majority of pregnancies deliver at a modal gestational age of 39 weeks, elective IOL would not necessarily be required for all women, but a standard of care emphasizing IOL at 39 weeks would lead to a significant increase of these procedures with their associated costs related to the interventions listed above \\u003csup\\u003e\\u003cspan additionalcitationids=\\\"CR41 CR42\\\" citationid=\\\"CR40\\\" class=\\\"CitationRef\\\"\\u003e40\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR43\\\" class=\\\"CitationRef\\\"\\u003e43\\u003c/span\\u003e\\u003c/sup\\u003e. Furthermore, it is concerning that resources allocated to IOL would decrease those available to care for high risk women as well as for those having a SOL. This concern may be misleading because they compare IOL to SOL \\u003csup\\u003e\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e\\u003c/sup\\u003e. The observed decrease in the cesarean section rates and improved perinatal outcomes would most likely be associated with decreased short and long-term costs. Even if short-term costs were similar, the improved perinatal outcomes would justify the intervention \\u003csup\\u003e\\u003cspan additionalcitationids=\\\"CR41 CR42\\\" citationid=\\\"CR40\\\" class=\\\"CitationRef\\\"\\u003e40\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR43\\\" class=\\\"CitationRef\\\"\\u003e43\\u003c/span\\u003e\\u003c/sup\\u003e.\\u003c/p\\u003e\\u003cp\\u003eOur findings are consistent with the most recently published studies and meta-analysis regarding elective induction of labor at 39 weeks gestation versus expectant management included women of advanced maternal age in one study and nulliparous women in the recent randomized controlled trial \\u003csup\\u003e\\u003cspan citationid=\\\"CR11\\\" class=\\\"CitationRef\\\"\\u003e11\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR15\\\" class=\\\"CitationRef\\\"\\u003e15\\u003c/span\\u003e, \\u003cspan additionalcitationids=\\\"CR18\\\" citationid=\\\"CR17\\\" class=\\\"CitationRef\\\"\\u003e17\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR19\\\" class=\\\"CitationRef\\\"\\u003e19\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR42\\\" class=\\\"CitationRef\\\"\\u003e42\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR44\\\" class=\\\"CitationRef\\\"\\u003e44\\u003c/span\\u003e,\\u003cspan citationid=\\\"CR45\\\" class=\\\"CitationRef\\\"\\u003e45\\u003c/span\\u003e\\u003c/sup\\u003e. Primary outcomes in these reports include cesarean delivery rates as well as composite neonatal outcome. Their results indicated that induction of labor at 39 weeks did not result in an increased rate of cesarean delivery and reported no increase in the rate of adverse neonatal outcomes.\\u003c/p\\u003e\\u003c/div\\u003e\"},{\"header\":\"Conclusions\",\"content\":\" \\u003cp\\u003eIn conclusion, our study demonstrates that in low-risk women induction of labor at 39 weeks gestation is benefits maternal or neonatal outcomes with significantly lower frequencies of maternal and neonatal morbidity when compared to expectant management through 42 weeks. We have also shown in secondary analysis that the risk for both maternal and fetal complications increases with each additional week of gestation after 39 weeks. Based on our study and supported by a growing body of literature, clinical protocols aimed at the avoidance of IOL at 39 weeks gestation in low-risk women seems unwarranted. Discussions should address the significant improvement in maternal and perinatal outcomes. The finding of increased rate of cesarean hysterectomy should be further investigated, particularly those factors that may potentially contribute to this complication.\\u003c/p\\u003e\"},{\"header\":\"Abbreviations\",\"content\":\"\\u003cp\\u003e\\u003cem\\u003eIOL: \\u003c/em\\u003eInduction of labor\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cem\\u003eSOL: \\u003c/em\\u003eSpontaneous onset of labor\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cem\\u003eTriple I: \\u003c/em\\u003eChorioamnionitis\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cem\\u003eNICU: \\u003c/em\\u003eNeonatal intensive care unit\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cem\\u003eaRR: \\u003c/em\\u003eAdjusted relative risk\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cem\\u003eRR: \\u003c/em\\u003eRelative risk\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cem\\u003eRCT\\u003c/em\\u003e\\u003cem\\u003e:\\u003c/em\\u003e Randomized controlled trial \\u003cem\\u003e\\u0026nbsp;\\u003c/em\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cem\\u003eNIH: \\u003c/em\\u003eNational Institutes of Health\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cem\\u003eNCHS: \\u003c/em\\u003eNational Center for Health Statistics\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cem\\u003eCDC: \\u003c/em\\u003eCenter for Disease Control and Prevention\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cem\\u003eBMI: \\u003c/em\\u003eBody mass index\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cem\\u003eSTROBE: \\u003c/em\\u003eStrengthening the Reporting of Observational Studies\\u003c/p\\u003e\"},{\"header\":\"Declarations\",\"content\":\"\\u003ch2\\u003eEthics approval and consent to participate:\\u003c/h2\\u003e\\n\\u003cp\\u003eThis study is a national retrospective cohort analysis using data abstracted from the NCHS and CDC\\u0026rsquo;s Division of Vital Statistics database. The data is publicly available and de-identified; therefore, no patients were directly involved and no ethics board approval was required.\\u003c/p\\u003e\\n\\u003ch2\\u003eConsent for publication:\\u003c/h2\\u003e\\n\\u003cp\\u003eAll contributing authors provided consent for publication.\\u003c/p\\u003e\\n\\u003ch2\\u003eAvailability of data and material:\\u003c/h2\\u003e\\n\\u003cp\\u003eAll data is publicly available from the webpage of the National Center for Health Statistics, a division of the CDC, and can be downloaded from \\u003ca href=\\\"https://www.cdc.gov/nchs/data_access/vitalstatsonline.htm\\\"\\u003ehttps://www.cdc.gov/nchs/data_access/vitalstatsonline.htm\\u003c/a\\u003e\\u003c/p\\u003e\\n\\u003ch2\\u003eDisclosures of interests:\\u003c/h2\\u003e\\n\\u003cp\\u003eNo conflicts of interest to declare.\\u003c/p\\u003e\\n\\u003ch2\\u003eFunding:\\u003c/h2\\u003e\\n\\u003cp\\u003eNo funding was required or requested to carry out this research\\u003c/p\\u003e\\n\\u003ch2\\u003eContribution to Authorship:\\u003c/h2\\u003e\\n\\u003cp\\u003eSC and RY planned the study and obtained the necessary data. All authors (SCB, RY, MD, JR, SC) contributed to the analysis of the data and interpretation of results. SCB drafted the manuscript and all other authors assisted with editing of the manuscript. All authors have accepted it in its final form.\\u003c/p\\u003e\\n\\u003ch2\\u003eAcknowledgements:\\u003c/h2\\u003e\\n\\u003cp\\u003eWe would like to thank the National Center for Health Statistics (NCHS) and Centers for Disease Control and Prevention\\u0026rsquo;s (CDC) Division of Vital Statistics for the creation and maintenance of this freely accessible database.\\u003c/p\\u003e\\n\\u003ch2\\u003eDisclosure\\u003c/h2\\u003e\\n\\u003cp\\u003eThe author(s) report no conflict of interest\\u003c/p\\u003e\\n\\u003cp\\u003e\\u0026nbsp;\\u003c/p\\u003e\"},{\"header\":\"References\",\"content\":\"\\u003col\\u003e\\n\\u003cli\\u003eMacer JA, Macer CL, Chan LS. 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Outcomes of elective labour induction and elective caesarean section in low-risk pregnancies between 37 and 41 weeks' gestation. \\u003cem\\u003eJ Obstet Gynaecol Can. \\u003c/em\\u003e2009;31(12):1124-1130.\\u003c/li\\u003e\\n\\u003cli\\u003eEhrenthal DB, Jiang X, Strobino DM. Labor induction and the risk of a cesarean delivery among nulliparous women at term. \\u003cem\\u003eObstet Gynecol. \\u003c/em\\u003e2010;116(1):35-42.\\u003c/li\\u003e\\n\\u003cli\\u003eLuthy DA, Malmgren JA, Zingheim RW. Cesarean delivery after elective induction in nulliparous women: the physician effect. \\u003cem\\u003eAmerican journal of obstetrics and gynecology. \\u003c/em\\u003e2004;191(5):1511-1515.\\u003c/li\\u003e\\n\\u003cli\\u003eVardo JH, Thornburg LL, Glantz JC. 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Outcomes of elective induction of labour compared with expectant management: population based study. \\u003cem\\u003eBmj. \\u003c/em\\u003e2012;344:e2838.\\u003c/li\\u003e\\n\\u003cli\\u003eCheng YW, Kaimal AJ, Snowden JM, Nicholson JM, Caughey AB. Induction of labor compared to expectant management in low-risk women and associated perinatal outcomes. \\u003cem\\u003eAmerican journal of obstetrics and gynecology. \\u003c/em\\u003e2012;207(6):502.e501-508.\\u003c/li\\u003e\\n\\u003cli\\u003eDarney BG, Snowden JM, Cheng YW, et al. Elective induction of labor at term compared with expectant management: maternal and neonatal outcomes. \\u003cem\\u003eObstet Gynecol. \\u003c/em\\u003e2013;122(4):761-769.\\u003c/li\\u003e\\n\\u003cli\\u003eMishanina E, Rogozinska E, Thatthi T, Uddin-Khan R, Khan KS, Meads C. Use of labour induction and risk of cesarean delivery: a systematic review and meta-analysis. \\u003cem\\u003eCMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne. \\u003c/em\\u003e2014;186(9):665-673.\\u003c/li\\u003e\\n\\u003cli\\u003eGrobman WA, Caughey AB. Elective induction of labor at 39 weeks compared\\u0026nbsp;with expectant management: a\\u0026nbsp;meta-analysis of cohort studies. \\u003cem\\u003eAmerican journal of obstetrics and gynecology. \\u003c/em\\u003e2019;221(4):304-310.\\u003c/li\\u003e\\n\\u003cli\\u003eMiddleton P, Shepherd E, Morris J, Crowther CA, Gomersall JC. Induction of labour at or beyond 37 weeks' gestation. \\u003cem\\u003eCochrane Database Syst Rev. \\u003c/em\\u003e2020;7(7):Cd004945.\\u003c/li\\u003e\\n\\u003cli\\u003eSaccone G, Della Corte L, Maruotti GM, et al. Induction of labor at full-term in pregnant women with uncomplicated singleton pregnancy: A systematic review and meta-analysis of randomized trials. \\u003cem\\u003eActa obstetricia et gynecologica Scandinavica. \\u003c/em\\u003e2019;98(8):958-966.\\u003c/li\\u003e\\n\\u003cli\\u003eGrobman WA, Rice MM, Reddy UM, et al. Labor Induction versus Expectant Management in Low-Risk Nulliparous Women. \\u003cem\\u003eThe New England journal of medicine. \\u003c/em\\u003e2018;379(6):513-523.\\u003c/li\\u003e\\n\\u003cli\\u003eSotiriadis A, Petousis S, Thilaganathan B, et al. Maternal and perinatal outcomes after elective induction of labor at 39 weeks in uncomplicated singleton pregnancy: a meta-analysis. \\u003cem\\u003eUltrasound in obstetrics \\u0026amp; gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology. \\u003c/em\\u003e2019;53(1):26-35.\\u003c/li\\u003e\\n\\u003cli\\u003eSociety of Maternal Fetal Medicine. SMFM Statement on Elective Induction of Labor in Low-Risk Nulliparous Women at Term: the ARRIVE Trial. \\u003cem\\u003eAmerican journal of obstetrics and gynecology. \\u003c/em\\u003e2019;221(1):B2-b4.\\u003c/li\\u003e\\n\\u003cli\\u003ePark BY, Cryer A, Betoni J, et al. Outcomes of labor induction at 39 weeks in pregnancies with a prior cesarean delivery. \\u003cem\\u003eThe journal of maternal-fetal \\u0026amp; neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstet. \\u003c/em\\u003e2020:1-6.\\u003c/li\\u003e\\n\\u003cli\\u003eWalker KF, Bugg GJ, Macpherson M, et al. Randomized Trial of Labor Induction in Women 35 Years of Age or Older. \\u003cem\\u003eThe New England journal of medicine. \\u003c/em\\u003e2016;374(9):813-822.\\u003c/li\\u003e\\n\\u003cli\\u003eNational Center for Health Statistics. 2021. https://www.cdc.gov/nchs/data_access/vitalstatsonline.htm. Accessed 02/02/2021.\\u003c/li\\u003e\\n\\u003cli\\u003eAmerican College of Obstetrics and Gynecology. ACOG Practice Bulletin No. 203: Chronic Hypertension in Pregnancy. \\u003cem\\u003eObstet Gynecol. \\u003c/em\\u003e2019;133(1):e26-e50.\\u003c/li\\u003e\\n\\u003cli\\u003eAmerican College of Obstetricians and Gynecologists. Gestational Hypertension and Preeclampsia: ACOG Practice Bulletin, Number 222. \\u003cem\\u003eObstet Gynecol. \\u003c/em\\u003e2020;135(6):e237-e260.\\u003c/li\\u003e\\n\\u003cli\\u003eAmerican College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 201: Pregestational Diabetes Mellitus. \\u003cem\\u003eObstet Gynecol. \\u003c/em\\u003e2018;132(6):e228-e248.\\u003c/li\\u003e\\n\\u003cli\\u003eAmerican College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 190: Gestational Diabetes Mellitus. \\u003cem\\u003eObstet Gynecol. \\u003c/em\\u003e2018;131(2):e49-e64.\\u003c/li\\u003e\\n\\u003cli\\u003eElsm\\u0026eacute;n E, K\\u0026auml;ll\\u0026eacute;n K, Mars\\u0026aacute;l K, Hellstr\\u0026ouml;m-Westas L. Fetal gender and gestational-age-related incidence of pre-eclampsia. \\u003cem\\u003eActa obstetricia et gynecologica Scandinavica. \\u003c/em\\u003e2006;85(11):1285-1291.\\u003c/li\\u003e\\n\\u003cli\\u003eMcNutt LA, Wu C, Xue X, Hafner JP. Estimating the relative risk in cohort studies and clinical trials of common outcomes. \\u003cem\\u003eAmerican journal of epidemiology. \\u003c/em\\u003e2003;157(10):940-943.\\u003c/li\\u003e\\n\\u003cli\\u003evon Elm E, Altman DG, Egger M, Pocock SJ, G\\u0026oslash;tzsche PC, Vandenbroucke JP. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: guidelines for reporting observational studies. \\u003cem\\u003eInternational journal of surgery (London, England). \\u003c/em\\u003e2014;12(12):1495-1499.\\u003c/li\\u003e\\n\\u003cli\\u003eThisted DL, Mortensen LH, Krebs L. Uterine rupture without previous caesarean delivery: a population-based cohort study. \\u003cem\\u003eEuropean journal of obstetrics, gynecology, and reproductive biology. \\u003c/em\\u003e2015;195:151-155.\\u003c/li\\u003e\\n\\u003cli\\u003eRydahl E, Eriksen L, Juhl M. Effects of induction of labor prior to post-term in low-risk pregnancies: a systematic review. \\u003cem\\u003eJBI database of systematic reviews and implementation reports. \\u003c/em\\u003e2019;17(2):170-208.\\u003c/li\\u003e\\n\\u003cli\\u003eLydon-Rochelle M, Holt VL, Easterling TR, Martin DP. Risk of uterine rupture during labor among women with a prior cesarean delivery. \\u003cem\\u003eThe New England journal of medicine. \\u003c/em\\u003e2001;345(1):3-8.\\u003c/li\\u003e\\n\\u003cli\\u003eS\\u0026oslash;rbye IK, Oppegaard KS, Weeks A, Marsdal K, Jacobsen AF. Induction of labor and nulliparity: A nationwide clinical practice pilot evaluation. \\u003cem\\u003eActa obstetricia et gynecologica Scandinavica. \\u003c/em\\u003e2020;99(12):1700-1709.\\u003c/li\\u003e\\n\\u003cli\\u003evan den Akker T, Brobbel C, Dekkers OM, Bloemenkamp KWM. Prevalence, Indications, Risk Indicators, and Outcomes of Emergency Peripartum Hysterectomy Worldwide: A Systematic Review and Meta-analysis. \\u003cem\\u003eObstet Gynecol. \\u003c/em\\u003e2016;128(6):1281-1294.\\u003c/li\\u003e\\n\\u003cli\\u003eMartin JA, Hamilton BE, Osterman MJK, Driscoll AK. Births: Final Data for 2018. \\u003cem\\u003eNational vital statistics reports : from the Centers for Disease Control and Prevention, National Center for Health Statistics, National Vital Statistics System. \\u003c/em\\u003e2019;68(13):1-47.\\u003c/li\\u003e\\n\\u003cli\\u003eAmerican College of Obstetricians and Gynecologists. Committee Opinion No 700: Methods for Estimating the Due Date. \\u003cem\\u003eObstet Gynecol. \\u003c/em\\u003e2017;129(5):e150-e154.\\u003c/li\\u003e\\n\\u003cli\\u003eKernberg A, Caughey AB. Augmentation of Labor: A Review of Oxytocin Augmentation and Active Management of Labor. \\u003cem\\u003eObstetrics and gynecology clinics of North America. \\u003c/em\\u003e2017;44(4):593-600.\\u003c/li\\u003e\\n\\u003cli\\u003eTsakiridis I, Mamopoulos A, Athanasiadis A, Dagklis T. Induction of Labor: An Overview of Guidelines. \\u003cem\\u003eObstetrical \\u0026amp; gynecological survey. \\u003c/em\\u003e2020;75(1):61-72.\\u003c/li\\u003e\\n\\u003cli\\u003eAssociation of Women\\u0026rsquo;s Health OaNN. Elective Induction of Labor. \\u003cem\\u003eNursing for women's health. \\u003c/em\\u003e2019;23(2):177-179.\\u003c/li\\u003e\\n\\u003cli\\u003eLittle SE. Elective Induction of Labor: What is the Impact? \\u003cem\\u003eObstetrics and gynecology clinics of North America. \\u003c/em\\u003e2017;44(4):601-614.\\u003c/li\\u003e\\n\\u003cli\\u003eHersh AR, Skeith AE, Sargent JA, Caughey AB. Induction of labor at 39 weeks of gestation versus expectant management for low-risk nulliparous women: a cost-effectiveness analysis. \\u003cem\\u003eAmerican journal of obstetrics and gynecology. \\u003c/em\\u003e2019;220(6):590.e591-590.e510.\\u003c/li\\u003e\\n\\u003cli\\u003eEinerson BD, Nelson RE, Sandoval G, et al. Cost of Elective Labor Induction Compared With Expectant Management in Nulliparous Women. \\u003cem\\u003eObstet Gynecol. \\u003c/em\\u003e2020;136(1):19-25.\\u003c/li\\u003e\\n\\u003cli\\u003eCaughey AB, Sundaram V, Kaimal AJ, et al. Maternal and neonatal outcomes of elective induction of labor. \\u003cem\\u003eEvidence report/technology assessment. \\u003c/em\\u003e2009(176):1-257.\\u003c/li\\u003e\\n\\u003cli\\u003eSouter V, Painter I, Sitcov K, Caughey AB. Maternal and newborn outcomes with elective induction of labor at term. \\u003cem\\u003eAmerican journal of obstetrics and gynecology. \\u003c/em\\u003e2019;220(3):273.e271-273.e211.\\u003c/li\\u003e\\n\\u003cli\\u003eWalker KF, Bugg G, Macpherson M, et al. Induction of labour versus expectant management for nulliparous women over 35 years of age: a multi-centre prospective, randomised controlled trial. \\u003cem\\u003eBMC pregnancy and childbirth. \\u003c/em\\u003e2012;12:145.\\u003c/li\\u003e\\n\\u003c/ol\\u003e\"}],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":true,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":false,\"hideJournal\":false,\"highlight\":\"\",\"institution\":\"\",\"isAcceptedByJournal\":true,\"isAuthorSuppliedPdf\":false,\"isDeskRejected\":\"\",\"isHiddenFromSearch\":false,\"isInQc\":false,\"isInWorkflow\":false,\"isPdf\":false,\"isPdfUpToDate\":true,\"isWithdrawnOrRetracted\":false,\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"researchsquare\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":true,\"externalIdentity\":\"\",\"sideBox\":\"\",\"snPcode\":\"\",\"submissionUrl\":\"/submission\",\"title\":\"Research Square\",\"twitterHandle\":\"researchsquare\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"\",\"reportingPortfolio\":\"\",\"inReviewEnabled\":false,\"inReviewRevisionsEnabled\":true},\"keywords\":\"induction of labor (IOL), maternal and perinatal outcomes, Relative risks (aRR), spontaneous onset of labor (SOL) \",\"lastPublishedDoi\":\"10.21203/rs.3.rs-289350/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-289350/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"\\u003cp\\u003e\\u003cem\\u003eObjective:\\u003c/em\\u003e To determine rates of maternal and perinatal outcomes after induction of labor (IOL) at 39 weeks compared with expectant management.\\u003c/p\\u003e\\u003cp\\u003e\\u003cem\\u003eMethods\\u003c/em\\u003e: Cohort study of low risk women delivered between 39-42 weeks from 2015 to 2018. We excluded births with fetal abnormalities, previous cesarean, multiple pregnancies or those with spontaneous onset of labor (SOL) or indicated delivery at 39 weeks. Data was abstracted from National Center for Health Statistics birth files. Relative risks (aRR) were estimated with multivariable log-binomial regression. \\u003c/p\\u003e\\u003cp\\u003e\\u003cem\\u003eMain Outcome Measures\\u003c/em\\u003e: Maternal outcomes: chorioamnionitis (Triple I), blood transfusion, neonatal intensive care unit (NICU) admission, uterine rupture, cesarean delivery and cesarean hysterectomy. Fetal and infant outcomes: fetal death, 5-minute Apgar ≤3, prolonged ventilation, seizures, ICU admission, and death within 28 days. \\u003c/p\\u003e\\u003cp\\u003e\\u003cem\\u003eResults:\\u003c/em\\u003e\\u0026nbsp;There were 15,900,956 births, with 8,540,063 after exclusions. The IOL group included 1,177,790 births excluding women with diabetes or hypertensive disease. There were 3,835,185 births after 39 weeks excluding women with diabetes or chronic hypertension. With IOL at 39 weeks the risk for blood transfusion (p-value \\u0026lt; 0.01; aRR 0.78; 95% CI [0.75-0.82]), Triple I (p-value \\u0026lt; 0.01; aRR 0.71; 95% CI [0.70-0.73]) and cesarean delivery (p-value \\u0026lt;0.01; aRR 0.87; 95% CI [0.87-0.88]) were lower, albeit increased risk of cesarean hysterectomy (p-value \\u0026lt;0.01; aRR 1.23; 95% CI [1.07-1.41]).\\u0026nbsp;Neonates had a lower risk for 5-minute Apgar ≤3 (p-value \\u0026lt; 0.01; aRR 0.68; 95% CI [0.66-0.71]), prolonged ventilation (p-value \\u0026lt; 0.01; aRR 0.84; 95% CI [0.81-0.87]), NICU admission (p-value \\u0026lt; 0.01; aRR 0.86; 95% CI [0.85-0.87]), and neonatal seizures (p-value\\u0026nbsp;\\u0026lt;0.01; aRR 0.85; 95% CI [0.76-0.96]). There was no difference in risk for neonatal death 0.99% (p-value 0.99; aRR 1.00; 95%CI [0.99-1.00]), or fetal death (p-value 0.78; aRR 1.0002; 95%CI [0.99-1.002]. This benefit was greater compared with each subsequent week.\\u003c/p\\u003e\\u003cp\\u003e\\u003cem\\u003eConclusions:\\u003c/em\\u003e Induction of labor at 39 weeks of gestation in a low risk cohort is associated a lower risk of cesarean delivery, transfusions and infection, as well as\\u0026nbsp;lower neonatal morbidity, without difference in fetal or neonatal death. This appears to be associated with increased risk for cesarean hysterectomy.\\u0026nbsp;\\u003c/p\\u003e\",\"manuscriptTitle\":\"Impact of Labor Induction at 39 Weeks Gestation Compared with Expectant Management on Maternal and Perinatal Morbidity among a Cohort of Low-risk Women\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2021-03-15 20:25:46\",\"doi\":\"10.21203/rs.3.rs-289350/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0}],\"status\":\"published\",\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"researchsquare\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":true,\"externalIdentity\":\"\",\"sideBox\":\"\",\"snPcode\":\"\",\"submissionUrl\":\"/submission\",\"title\":\"Research Square\",\"twitterHandle\":\"researchsquare\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"\",\"reportingPortfolio\":\"\",\"inReviewEnabled\":false,\"inReviewRevisionsEnabled\":true}}],\"origin\":\"\",\"ownerIdentity\":\"4e2280c4-ffba-4c53-a11a-b05312389da3\",\"owner\":[],\"postedDate\":\"March 15th, 2021\",\"published\":true,\"recentEditorialEvents\":[],\"rejectedJournal\":[],\"revision\":\"\",\"amendment\":\"\",\"status\":\"published-in-journal\",\"subjectAreas\":[{\"id\":2978905,\"name\":\"Maternal \\u0026 Fetal Medicine\"}],\"tags\":[],\"updatedAt\":\"2021-12-30T02:43:44+00:00\",\"versionOfRecord\":{\"articleIdentity\":\"rs-289350\",\"link\":\"https://doi.org/10.1080/14767058.2021.2021396\",\"journal\":{\"identity\":\"the-journal-of-maternal-fetal-and-neonatal-medicine\",\"isVorOnly\":true,\"title\":\"The Journal of Maternal-Fetal \\u0026 Neonatal Medicine\"},\"publishedOn\":\"2021-12-29 02:43:44\",\"publishedOnDateReadable\":\"December 29th, 2021\"},\"versionCreatedAt\":\"2021-03-15 20:25:46\",\"video\":\"\",\"vorDoi\":\"10.1080/14767058.2021.2021396\",\"vorDoiUrl\":\"https://doi.org/10.1080/14767058.2021.2021396\",\"workflowStages\":[]},\"version\":\"v1\",\"identity\":\"rs-289350\",\"journalConfig\":\"researchsquare\"},\"__N_SSP\":true},\"page\":\"/article/[identity]/[[...version]]\",\"query\":{\"redirect\":\"/article/rs-289350\",\"identity\":\"rs-289350\",\"version\":[\"v1\"]},\"buildId\":\"_2-kVJe1T_tPrBINL-cwx\",\"isFallback\":false,\"isExperimentalCompile\":false,\"dynamicIds\":[84888],\"gssp\":true,\"scriptLoader\":[]}","source_license":"CC-BY-4.0","license_restricted":false}