Pregnancy and Neonatal Outcomes in Women with Arcuate Uterus: A Population-Based Cohort Study of Over 3.8 Million Women

Pregnancy and Neonatal Outcomes in Women with Arcuate Uterus: A Population-Based Cohort Study of Over 3.8 Million 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 Pregnancy and Neonatal Outcomes in Women with Arcuate Uterus: A Population-Based Cohort Study of Over 3.8 Million Women Nir Kugelman, Ella M. Gangbe, Ahmad Badeghiesh, Haitham Baghlaf, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6560372/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 28 Oct, 2025 Read the published version in BMC Pregnancy and Childbirth → Version 1 posted 11 You are reading this latest preprint version Abstract Background: Congenital uterine anomalies are associated with adverse reproductive outcomes, yet the impact of the arcuate uterus remains unclear due to limited sample sizes and inconsistent findings in previous studies. We utilized a large population database to assess pregnancy, delivery, and neonatal outcomes in women with an arcuate uterus. Methods: Retrospective population-based study using data from the Health Care Cost and Utilization Project-Nationwide Inpatient Sample. Cases of arcuate uterus were identified using ICD code 752.36. Pregnancies in women with an arcuate uterus were matched to 3,016 pregnancies in women without congenital uterine anomalies (1 to 4) and compared to the entire population without congenital anomalies. Multivariate logistic regression adjusted for confounding variables. Results: Among 3,841,147 control births and 754 births in women with an arcuate uterus, more of these women were older than 25 and had higher rates of previous cesarean sections (CS), in-vitro pregnancies, and multiple gestations (all P<0.01). Pregnancy outcomes showed higher rates of pregnancy-induced hypertension (adjusted odds ratio (aOR) 1.32), preeclampsia (aOR 1.63), premature preterm rupture of membranes (aOR 2.86), preterm delivery (aOR 1.86), placental abruption (aOR 3.08), CS (aOR 10.88), and small for gestational age (SGA) neonates (aOR 2.21) (all 95%CI excluding 1). Compared to the matched cohort, women with an arcuate uterus had higher rates of pregnancy-induced hypertension (aOR 1.76), preeclampsia (aOR 2.08), premature preterm rupture of membranes (aOR 2.46), preterm delivery (aOR 2.74), placental abruption (aOR 2.11), postpartum hemorrhage (aOR 1.67), wound complications (aOR 3.42), CS (aOR 30.04), disseminated intravascular coagulopathy (DIC) (aOR 5.36), and SGA (aOR 1.76) (all 95%CI excluding 1). Conclusions: Women with an arcuate uterus are at increased risk of adverse pregnancy outcomes, particularly CS and DIC. Enhanced surveillance and preventive measures are recommended. arcuate uterus cohort studies pregnancy complications pregnancy outcome uterine anomalies Figures Figure 1 BACKGROUND Congenital uterine anomalies (CUAs) affect about 5% of women and are linked to adverse health outcomes [ 1 ]. In non-pregnant women, CUAs can cause hematometra, hematocolpos, endometriosis, pelvic pain, abnormal uterine bleeding, and genital and urinary tract infections [ 2 ]. Additionally, 20–30% of individuals with Müllerian anomalies present with renal anomalies and other malformations, including cardiac defects [ 3 – 5 ]. In pregnant women, CUAs increase the risk of first and second-trimester miscarriages, preterm delivery, malpresentation, cesarean section (CS), and small for gestational age (SGA) neonates [ 6 – 7 ]. Women with infertility also show higher rates of uterine malformations [ 8 ]. These adverse outcomes are primarily associated with uterus didelphys, bicornuate uterus, and septate uterus [ 3 ]. The arcuate uterus, a common CUA, is characterized by a slight indentation of less than a centimeter at the fundus with an angle above 90 degrees [ 9 ]. Most women with an arcuate uterus are asymptomatic, often diagnosed incidentally during ultrasonography [ 10 ]. Compared to other CUAs, the arcuate uterus appears to have fewer adverse effects on pregnancies. For instance, Woelfer et al. reported a slight increase in second-trimester pregnancy losses and preterm labor among women with an arcuate uterus [ 11 ], while Mucowski et al. found no significant impact on reproductive outcomes in a smaller study [ 12 ]. Most literature focuses on more significant uterine anomalies such as bicornuate or unicornuate uteri since arcuate uterus is often considered a variation of normal [ 12 ] or combines all CUAs. Studies specifically examining the effects of the arcuate uterus on pregnancy outcomes involved only a small number of participants, potentially lacking the power to detect significant differences. The largest study on this topic examined 420 cases of arcuate uterus and small septum combined [ 13 ]. Additionally, findings in the literature are conflicting. This study aims to clarify the pregnancy, delivery, and neonatal outcomes of women with an arcuate uterus using a large population database. METHODS Data Source We conducted a retrospective population-based cohort study using data from the Health Care Cost and Utilization Project-Nationwide Inpatient Sample (HCUP-NIS) from 2010 to 2014. The HCUP-NIS database contains data on hospital inpatient stays and represents the largest publicly available all-payer inpatient database in the United States, covering over 97% of inpatient discharges from U.S. community hospitals. Data collection is managed by federal and state agencies, hospital associations, and private organizations. Data elements before 2015 are coded using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). Study Population In-hospital births occurring between 2010 and 2014 were included in the study. Births were identified using ICD-9-CM diagnostic codes (634x-679x, V22x, V23x, V27x) and procedural codes (72x-75x). Each pregnancy was included only once. In-hospital admissions resulting in delivery or maternal death were identified using specific ICD-9-CM codes (650x, 677x, 651x-676x) and procedural codes (72x, 73x, 74.0, 74.1, 74.2, 74.4, 74.99). Women with an arcuate uterus were identified using ICD-9-CM diagnostic code 752.36. Women without uterine anomalies served as the control group. Data Collection Baseline characteristics recorded included age, race, type of insurance, income, body mass index (BMI) (obese BMI ≥ 30 kg/m² versus non-obese BMI < 30 kg/m²), previous CS, smoking history, pre-existing hypertension, diabetes, thyroid disease, drug use, HIV status, use of in in vitro fertilization (IVF), and presence of multiple gestation. Pregnancy outcomes assessed included pregnancy-induced hypertension (PIH), chronic hypertension with superimposed preeclampsia, gestational hypertension, preeclampsia, eclampsia, gestational diabetes, and placenta previa. Delivery outcomes included preterm premature rupture of membranes (PPROM), preterm delivery, placental abruption, chorioamnionitis, mode of delivery (operative vaginal delivery, CS, spontaneous vaginal delivery (SVD)), hysterectomy, postpartum haemorrhage (PPH), wound complications, maternal death, blood transfusion, maternal infection, venous thromboembolism (VTE), and disseminated intravascular coagulopathy (DIC). Deep vein thrombosis (DVT) and pulmonary embolism (PE) were included under VTE. Neonatal outcomes included SGA, intrauterine fetal demise, and congenital anomalies. Statistical Analysis An unmatched and a matched analysis were performed. Each case of arcuate uterus was matched to four controls based on age, race, income, and insurance type. Statistically significant differences in baseline characteristics between women with and without an arcuate uterus were compared using Chi-Squared or Fisher’s exact tests. Maternal and neonatal outcomes were compared using univariate and multivariate logistic regression analyses adjusted for confounding variables (characteristics with p < 0.05). Analyses were conducted using SPSS 23.0 software. Statistical significance was set at p < 0.05. RESULTS A total of 3,851,029 births occurred during the study period, including 754 from women with an arcuate uterus and 3,840,147 from women without CUAs (control group). Additionally, 10,128 births from women with other CUAs were excluded. The 754 births from women with an arcuate uterus were matched to 3,016 control births. The prevalence of arcuate uterus between 2010 and 2014 was 19.58 per 100,000 births, with a significant increase over time from 4.74 per 100,000 in 2010 to 31.68 per 100,000 in 2014 (p < 0.001) (Fig. 1 ). Baseline Characteristics Women with an arcuate uterus were more likely to be older than 25 years, Caucasian, in a higher income quartile, and have private insurance compared to the control group (all p < 0.001) (Table 1 ). They were also more likely to have had a previous CS (p < 0.001), pre-gestational diabetes (p = 0.03), thyroid disease (p < 0.001), IVF pregnancies (p < 0.01), and multiple gestations (p < 0.01). In the matched group, women with an arcuate uterus were more likely to have had a previous CS (p < 0.001) and thyroid disease (p = 0.02). Table 1 Maternal characteristics of the 3,840,901 births that occurred between 2004 to 2014 Characteristics Arcuate Uterus N = 754 No Arcuate Uterus N = 3,840,147 p-value Age (years) < 0.001 < 25 182 (24.1%) 1379779 (35.8%) 25–34 443 (58.7%) 1894732 (49.3%) ≥ 35 128 (17.0%) 572637 (14.9%) Race < 0.001 White 534 (70.8%) 2036437 (53.0%) Black 29 (3.8%) 560659 (14.6%) Hispanic 117 (15.5%) 825628 (21.5%) Asian and Pacific 42 (5.6%) 20736 (5.4%) Native American 5 (0.7% 30721 (0.8%) Other 28 (3.7%) 184327 (4.8%) Income quartiles < 0.001 Less than 39,000 118 (15.6%) 1063521 (27.7%) $ 39,000–47,999 167 (22.2%) 960037 (25.0%) $ 48,000–62,999 224 (29.7%) 967705 (25.2%) $ 63,000 or more 245 (32.5%) 848589 (22.1%) Plan type < 0.001 Medicare 8 (1.1%) 26881 (0.7%) Medicaid 191 (25.3%) 1686081 (43.9%) Private including Health Maintenance Organizations 511 (67.8%) 1911655 (49.8%) Self-pay 18 (2.4%) 99844 (2.6%) No charge 0 (0.0%) 3840 (0.1%) Other 26 (3.4%) 111364 (2.9%) Obesity 46 (6.1%) 211207 (5.5%) 0.50 Previous cesarean section 194 (25.7%) 656486 (17.1%) < 0.001 Smoking during pregnancy 41 (5.4%) 211207 (5.5%) 0.98 Chronic hypertension 16 (2.1%) 84483 (2.2%) 0.93 Pregestational diabetes 13 (1.7%) 38401 (1.0%) 0.03 Drug use 14 (1.9%) 61442 (1.6%) 0.64 Thyroid disease 48 (6.4%) 119045 (3.1%) < 0.001 HIV 0 (0.0%) 0 (0.0%) 1.00 In vitro fertilization 6 (0.8%) 7680 (0.2%) < 0.01 Multiple gestation 25 (3.3%) 65282 (1.7%) < 0.01 HIV = Human immunodeficiency virus Pregnancy Outcomes Pregnancy outcomes in both matched and unmatched groups showed that women with an arcuate uterus had higher risks of PIH (adjusted odd ratio (aOR) 1.76, 95% CI 1.34–2.32 in the matched group; aOR 1.32, 95% CI 1.03–1.70 in the unmatched group) and preeclampsia (aOR 2.08, 95% CI 1.45–2.98 in the matched group; aOR 1.63, 95% CI 1.18–2.24 in the unmatched group) (Table 2 ). However, they were not at higher risk for gestational hypertension, eclampsia, chronic hypertension with superimposed preeclampsia, gestational diabetes, or placenta previa. Table 2 Pregnancy, delivery and other outcomes of the 3,840,901 births that occurred between 2010 to 2014 Outcomes Arcuate uterus n = 754 No Arcuate Uterus n = 3,840,147 Crude Odds Ratio (95% Confidence Interval) Adjusted Odds Ratio (95% Confidence Interval) Adjusted p-value Pregnancy outcomes † Pregnancy induced HTN 82 (10.9%) 307212 (8.0%) 1.40 (1.11–1.76) 1.32 (1.03–1.70) 0.03 Gestational HTN 30 (4.0%) 141085 (3.7%) 1.09 (0.76–1.58) 1.02 (0.70–1.51) 0.92 Preeclampsia 48 (6.4%) 145925 (3.8%) 1.72 (1.29–2.31) 1.63 (1.18–2.24) < 0.01 Eclampsia 1 (0.1%) 3840 (0.1%) 1.94 (0.27–13.8) 2.55 (0.36–18.12) 0.35 Preeclampsia and Eclampsia superimposed HTN 6 (0.8%) 23041 (0.6%) 1.25 (0.56–2.80) 1.22 (0.51–2.96) 0.66 GDM 57 (7.6%) 249609 (6.5%) 1.18 (0.90–1.55) 1.07 (0.80–1.43) 0.66 Placenta previa 6 (0.8%) 23041 (0.6%) 1.40 (0.63–3.12) 1.11 (0.46–2.69) 0.81 Delivery outcomes ‡ PPROM 25 (3.3%) 42242 (1.1%) 2.96 (1.99–4.41) 2.86 (1.86–4.40) < 0.001 Preterm delivery 90 (11.9%) 253448 (6.6%) 1.92 (1.54–2.40) 1.86 (1.45–2.37) < 0.001 Abruptio placenta 22 (2.9%) 42242 (1.1%) 2.81 (1.84–4.29) 3.08 (1.99–4.77) < 0.001 Chorioamnionitis 16 (2.1%) 72963 (1.9%) 1.11 (0.67–1.81) 1.21 (0.71–2.06) 0.48 Operative vaginal delivery 16 (1.2%) 180285 (4.7%) 0.25 (0.13–0.47) 0.26 (0.13–0.52) < 0.001 Cesarean section 612 (81.2%) 1255948 (32.7%) 8.82 (7.35–10.59) 10.88 (8.90–13.30) < 0.001 Spontaneous vaginal delivery 133 (17.6%) 2395092 (62.4%) 0.13 (0.11–0.16) 0.12 (0.10–0.14) < 0.001 Hysterectomy 0 (0.0%) 3840 (0.1%) - - - PPH 32 (4.2%) 115204 (3.0%) 1.42 (0.99–2.02) 1.43 (0.99–2.08) 0.06 Wound complications 7 (0.9%) 11520 (0.3%) 2.81 (1.34–5.92) 2.14 (0.95–4.78) 0.07 Maternal death 0 (0.0%) 0 (0.0%) - - - Transfusion 14 (1.9%) 46082 (1.2%) 1.56 (0.92–2.65) 1.50 (0.84–2.66) 0.17 Others Maternal infection 18 (2.4%) 88323 (2.3%) 1.05 (0.66–1.68) 1.18 (0.72–1.94) 0.52 DVT 0 (0.0%) 0 (0.0%) - - - Pulmonary embolism 2 (0.3%) 0 (0.0%) 13.58 (3.38–54.49) 15.14 (3.76–60.91) < 0.001 VTE 2 (0.3%) 3840 (0.1%) 4.61 (1.15–18.50) 4.81 (1.20–19.30) 0.03 DIC 4 (0.5%) 7680 (0.2%) 2.17 (0.81–5.80) 2.19 (0.82–5.88) 0.12 † Pregnancy outcomes: Adjusted for Age, Race, Plan types, Income quartiles, Previous cesarean section, Thyroid disease, Multiple gestation, Pregestational diabetes and IVF ‡ Delivery outcomes: Adjusted for Age, Race, Plan types, Income quartiles, Previous cesarean section, Thyroid disease, Multiple gestation, Pregestational diabetes, IVF, Pregnancy induce hypertension and Preeclampsia HTN = hypertension; GDM = gestational diabetes mellitus; PPROM = premature rupture of membranes; PPH = post-partum hemorrhage; DVT = deep vein thrombosis; VTE = venous thromboembolism; DIC = disseminated intravascular coagulation Delivery Outcomes Women with an arcuate uterus were more likely to experience PPROM (aOR 2.46, 95% CI 1.48–4.09 in the matched group; aOR 2.86, 95% CI 1.86–4.40 in the unmatched group), preterm delivery (aOR 2.74, 95% CI 2.06–3.65 in the matched group; aOR 1.86, 95% CI 1.45–2.37 in the unmatched group), and placental abruption (aOR 2.11, 95% CI 1.23–3.63 in the matched group; aOR 3.08, 95% CI 1.99–4.77 in the unmatched group) (Table 2 ). They also had significantly higher odds of delivering via CS (aOR 30.04, 95% CI 23.99–37.63 in the matched group; aOR 10.88, 95% CI 8.90–13.30 in the unmatched group) and were much less likely to have a spontaneous vaginal delivery (SVD) (aOR 0.04, 95% CI 0.03–0.05 in the matched group; aOR 0.12, 95% CI 0.10–0.14 in the unmatched group). In the matched cohort, women with an arcuate uterus had higher odds of PPH (aOR 1.67, 95% CI 1.09–2.56), wound complications (aOR 3.42, 95% CI 1.18–9.96), and DIC (aOR 5.58, 95% CI 1.21–25.60). In the unmatched group, they had higher odds of VTE (aOR 4.81, 95% CI 1.20–19.30) PE (aOR 15.14, 95% CI 3.76–60.91). No maternal deaths were reported in either group, and no significant differences were found in other reported outcomes. Neonatal Outcomes Deliveries from women with an arcuate uterus had a 5.7% rate of SGA neonates compared to 3.2% in the matched control group (aOR 1.76, 95% CI 1.21–2.56) and 2.6% in the unmatched control group (aOR 2.21, 95% CI 1.58–3.10) (Table 3 ). Rates of intrauterine fetal demise and congenital anomalies were similar between the groups in both the matched and unmatched cohorts. Table 3 Neonatal outcomes of the 3,840,901 births that occurred between 2010 to 2014 Outcomes † Arcuate uterus N = 754 No Arcuate Uterus N = 3,840,147 Crude Odds Ratio (95% Confidence Interval) Adjusted Odds Ratio (95% Confidence Interval) Adjusted p-value Small for gestational age 43 (5.7%) 99844 (2.6%) 2.30 (1.69–3.13) 2.21 (1.58–3.10) < 0.001 Intra uterine fetal demise 5 (0.7%) 15361 (0.4%) 1.59 (0.66–3.83) 1.97 (0.82–4.75) 0.13 Congenital anomalies 0 (0.0%) 11520 (0.3%) - - - † Neonatal outcomes: Adjusted for Age, Race, Plan type, Income quartiles, Previous cesarean section, Thyroid Disease, Multiple gestation, Pregestational diabetes, IVF, Pregnancy induced hypertension and Preeclampsia. DISCUSSION This large-scale, population-based study is the first to evaluate the impact of an arcuate uterus on obstetrical and neonatal outcomes using a substantial cohort. Our findings indicate that women with an arcuate uterus have higher risks of several complications, including PIH, preeclampsia, preterm delivery, PPROM, placental abruption, CS, PPH, and wound complications. Despite these increased risks, rates of intrauterine fetal demise and congenital anomalies were similar between women with and without an arcuate uterus. Additionally, deliveries in women with an arcuate uterus showed higher odds of SGA neonates. The arcuate uterus is one of the most common CUAs. The reported prevalence varies depending on the population studied and the mode of diagnosis. In a systematic review, Chan et al. demonstrated a prevalence of 3.9% of arcuate uterus in an unselected population [ 1 ]. In studies estimating the prevalence of CUAs in women with fertility issues, the arcuate uterus was found in 12–16% of that specific population [ 14 – 16 ]. Our results demonstrate a prevalence of an arcuate uterus of 19.58 per 100,000 births from 2010 to 2014. This lower number likely represents a low sensitivity for diagnosis of this anomaly but a high specificity of diagnosis in this database. Such a distribution should not compromise the results of this study. If anything, they may slightly underestimate the risks of the arcuate uterus in pregnancy. Our results also show a statistically significant increase in the incidence of the arcuate uterus over time, possibly due to increased detection and diagnosis over the years. Women with an arcuate uterus had a higher incidence of pregnancy-induced hypertension and preeclampsia. Not many studies have specifically looked at this outcome in CUAs. Fox et al. described the possibility of unilateral placental implantation and functional exclusion of one of the uterine arteries as potential causes for increased rates of intrauterine growth restriction and preeclampsia in women with major uterine anomalies. In their study, the arcuate uterus did not seem to be associated with increased preeclampsia; however, they had only 14 cases with the malformation, which might not have provided enough power to detect the risk of preeclampsia [ 6 ]. It is thus unclear if the arcuate uterus could also lead to abnormal placentation and possible hypertensive disorders during pregnancy. As demonstrated by others, the arcuate uterus was also associated with thirty times the rates of CS delivery and lower rates of spontaneous vaginal delivery. This could be explained by the fact that malpresentations and placental abruption are more common [ 17 – 18 ]. Thus, it is not surprising that these women were more likely to have had CS in the past. Higher rates of CS and the associated coagulopathy, as well as the possible higher risk of hypertensive disorders in pregnancy, could directly explain why women with an arcuate uterus had a higher risk of postpartum hemorrhage and five times more DIC. This increase in the risk of postpartum hemorrhage and DIC was only found in the matched cohort. In the unmatched cohort, women with an arcuate uterus had twelve times more PE and five times more deep vein thrombosis events. This difference was not found once the cases were matched to controls. The increased risk of DIC noted in our results might not, however, be significant, as only a very small number of women suffered from these outcomes. It is unlikely that the arcuate uterus itself would cause an increased risk of coagulability. In our study, women with an arcuate uterus demonstrated about twice the risk for PPROM, preterm delivery, and SGA. Most of the published literature recognizes these risks with CUAs as a whole but not necessarily with the arcuate uterus [ 13 , 19 – 20 ]. Lekovich et al. suggested placental malperfusion as a possible cause of preterm delivery in women with uterine anomalies. Placental malperfusion is also a recognized cause of small neonates [ 18 ]. Woelfer et al. and Fox et al. found that women with an arcuate uterus had higher rates of second-trimester miscarriage and preterm delivery compared to those with a normal uterus. Their respective study populations included 72 and 14 women with the anomaly [ 6 , 11 ]. However, a systematic review of 12 articles looking partly at the outcomes of the arcuate uterus did not find any of these differences, although the relative risk was marginally insignificant at 2.04 (95% CI 0.99 to 4.1) [ 21 ]. Our larger cohort might have provided sufficient power to confirm that the arcuate uterus is indeed associated with risks of PPROM, preterm delivery, and SGA. Whether metroplasty of the arcuate uterus improves pregnancy outcomes is controversial. One prospective study of 96 women with arcuate and septate uteri found no difference in outcomes [ 22 ]. Conversely, a larger retrospective study of 420 small septums and arcuate uteri reported a decrease in the rate of preterm birth from 34% before hysteroscopic resection to 7% after, and a decrease in the rate of extreme preterm birth from 13–3% [ 13 ]. A recent case-control study by also looked at the pregnancy outcomes of 37 women with an arcuate uterus compared to 165 women with similar baseline characteristics and no congenital uterine anomalies. Similar to our study, their results showed that women with an arcuate uterus were at increased risk of spontaneous preterm birth and had lower mean birthweight. However, there were no differences in the risks of preeclampsia or CS [ 23 ]. The study has limitations, such as its retrospective nature and reliance on ICD-9-CM codes for identifying arcuate uterus cases, which might introduce classification bias. Additionally, the database lacks detailed clinical data on the method of diagnosis and severity of the arcuate uterus, potentially influencing pregnancy outcomes. This raises the possibility that some cases might have been misclassified, including women with a low-level septate uterus rather than an arcuate uterus, introducing further bias into our findings. Moreover, the database lacks information on various confounding factors, such as fertility status (partially inferred from IVF use), previous pregnancy losses, parity, indications for cesarean section, history of coagulopathies, and previous adverse pregnancy or neonatal outcomes. These gaps limit our ability to fully account for all variables that might influence the observed outcomes, although these complications could directly result from the presence of an arcuate uterus itself. The strengths of this study include its large cohort size, making it the most extensive study to date examining pregnancy, delivery, and neonatal outcomes associated with the arcuate uterus. The study design involved matching cases of arcuate uterus to controls, and we adjusted for confounding variables using multivariate logistic regression analysis. This robust methodology enhances confidence in our findings despite the heterogeneity in the existing literature. Additionally, even if some subjects had low-level septate uteri rather than truly arcuate uteri, the results likely reflect the complications in the population diagnosed with arcuate uteri. We expect the rate of misdiagnosis to be consistent between our study and the general population, thereby supporting the generalizability of our findings. Consequently, our results provide valuable insights that can guide practitioners in understanding and managing the pregnancy risks associated with an arcuate uterus. CONCLUSIONS Women with an arcuate uterus are at significantly increased risk for several adverse pregnancy outcomes, including PIH, preeclampsia, PPROM, preterm delivery, placental abruption, CS, PPH, DIC, SGA neonates, and wound complications. These findings highlight the importance of targeted monitoring and management strategies for this population. Our results differ from those of some smaller cohorts. Therefore, further large-scale studies are needed to confirm these findings and to develop effective interventions to improve pregnancy outcomes for women with an arcuate uterus. Abbreviations CUAs: Congenital uterine anomalies; CS: Cesarean section; SGA: Small for gestational age; HCUP-NIS: Project-Nationwide Inpatient Sample; ICD-9-CM: International Classification of Diseases, Ninth Revision, Clinical Modification; BMI: Body mass index; IVF: In vitro fertilization; PIH: Pregnancy-induced hypertension; PPROM: Preterm premature rupture of membranes; SVD: Spontaneous vaginal delivery; PPH: Postpartum haemorrhage; VTE: Venous thromboembolism; DIC: Disseminated intravascular coagulopathy; DVT: Deep vein thrombosis; PE: Pulmonary embolism; aOR: Adjusted odd ratio; CI: Confidence interval Declarations Ethics approval and consent to participate This study used de-identified, publicly available data and was conducted in accordance with the ethical standards of the Tri-Council Policy Statement: Ethical Conduct for Research Involving Humans (TCPS 2, 2010) and the principles of the Declaration of Helsinki. Institutional review board approval was not required. Informed consent was not applicable due to the retrospective nature of the study. Consent for publication Not applicable Availability of data and materials The dataset supporting the conclusions of this article is available in the Health Care Cost and Utilization Project-Nationwide Inpatient Sample (HCUP-NIS) repository, https://health.gov/healthypeople/objectives-and-data/data-sources-and-methods/data-sources/healthcare-cost-and-utilization-project-national-nationwide-inpatient-sample-hcup-nis. Competing Interests The authors declare that they have no competing interests Funding None Authors' contributions NK, EMG, MHD contributed in conception, design and drafting of the manuscript. NK, EMG, AB, HB, and MHD contributed in data collection, analysis and interpretation of data. All authors reviewed and approved the final version for submission. Acknowledgements Not applicable References Chan YY, Jayaprakasan K, Zamora J, Thornton JG, Raine-Fenning N, Coomarasamy A. 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Lekovich J, Stewart J, Anderson S, Niemasik E, Pereira N, Chasen S. Placental malperfusion as a possible mechanism of preterm birth in patients with Müllerian anomalies. J Perinat Med. 2017;45(1):45–9. Saravelos SH, Cocksedge KA, Li T-C. The pattern of pregnancy loss in women with congenital uterine anomalies and recurrent miscarriage. Reprod Biomed Online. 2010;20(3):416–22. Carbonnel M, Pirtea P, de Ziegler D, Ayoubi JM. Uterine factors in recurrent pregnancy losses. Fertil Steril. 2021;115(3):538–45. Venetis CA, Papadopoulos SP, Campo R, Gordts S, Tarlatzis BC, Grimbizis GF. Clinical implications of congenital uterine anomalies: a meta-analysis of comparative studies. Reprod Biomed Online. 2014;29(6):665–83. Gergolet M, Campo R, Verdenik I, Kenda Suster N, Gordts S, Gianaroli L. No clinical relevance of the height of fundal indentation in subseptate or arcuate uterus: a prospective study. Reprod Biomed Online. 2012;24(5):576–82. Connolly CT, Hill MB, Klahr RA, Zafman KB, Rebarber A, Fox NS. Arcuate uterus as an independent risk factor for adverse pregnancy outcomes. Am J Perinatol. 2024;41(2):167–73. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 28 Oct, 2025 Read the published version in BMC Pregnancy and Childbirth → Version 1 posted Editorial decision: Revision requested 11 Aug, 2025 Reviews received at journal 27 Jul, 2025 Reviews received at journal 15 Jun, 2025 Reviewers agreed at journal 09 Jun, 2025 Reviewers agreed at journal 09 Jun, 2025 Reviewers agreed at journal 03 Jun, 2025 Reviewers invited by journal 28 May, 2025 Editor invited by journal 05 May, 2025 Editor assigned by journal 02 May, 2025 Submission checks completed at journal 02 May, 2025 First submitted to journal 29 Apr, 2025 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. 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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-6560372","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":462930073,"identity":"f9479d33-e582-4971-940e-65db384695f6","order_by":0,"name":"Nir Kugelman","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyElEQVRIiWNgGAWjYDACZiBkqAAyJBgYDkCEGBsPENZyxgBFSwN+LSBNjG0QLXCAV4s5O+9jY955f+T4Z/cePPBxB4M8fwMzflssm9mNk3m3GRhL3DmXcHDmGQbDGQcIOMzgMBvzYaCWxA0SOQaHedsYGDcQ8gtEyxyDepgWe6K0JPM2GCQYQLUkEqXFcM4xY8MZN3IMDs5sk0iecZiQlvPHmCXe1MjJ88/IMf7wsc3Gtr+9/eEDfFrQgQQonkbBKBgFo2AUUAoAJWVGMWpisQ0AAAAASUVORK5CYII=","orcid":"","institution":"Technion – Israel Institute of Technology","correspondingAuthor":true,"prefix":"","firstName":"Nir","middleName":"","lastName":"Kugelman","suffix":""},{"id":462930074,"identity":"e21a3278-cd0c-40df-9b9e-1a4a8e105e92","order_by":1,"name":"Ella M. Gangbe","email":"","orcid":"","institution":"McGill University","correspondingAuthor":false,"prefix":"","firstName":"Ella","middleName":"M.","lastName":"Gangbe","suffix":""},{"id":462930075,"identity":"1889b098-e26b-4536-8705-d4f0028b0aa9","order_by":2,"name":"Ahmad Badeghiesh","email":"","orcid":"","institution":"Western University","correspondingAuthor":false,"prefix":"","firstName":"Ahmad","middleName":"","lastName":"Badeghiesh","suffix":""},{"id":462930076,"identity":"e22b2cd9-c3f8-4ac7-ad00-804cb3ccd30c","order_by":3,"name":"Haitham Baghlaf","email":"","orcid":"","institution":"University of Toronto","correspondingAuthor":false,"prefix":"","firstName":"Haitham","middleName":"","lastName":"Baghlaf","suffix":""},{"id":462930077,"identity":"5e94cdc1-9e63-45f4-82f1-db7504f82b0c","order_by":4,"name":"Michael H. Dahan","email":"","orcid":"","institution":"McGill University","correspondingAuthor":false,"prefix":"","firstName":"Michael","middleName":"H.","lastName":"Dahan","suffix":""}],"badges":[],"createdAt":"2025-04-30 02:38:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6560372/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6560372/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12884-025-08125-7","type":"published","date":"2025-10-28T15:58:34+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":83648951,"identity":"4cad3288-46a7-4273-8892-68c823dc8638","added_by":"auto","created_at":"2025-05-30 06:24:05","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":308343,"visible":true,"origin":"","legend":"\u003cp\u003ePrevalence of arcuate uterus among the 3,840,901 births that occurred between 2010 and 2014\u003c/p\u003e","description":"","filename":"Figure1highresolutionPNG.png","url":"https://assets-eu.researchsquare.com/files/rs-6560372/v1/164adfe8a151026c5753de5c.png"},{"id":95040715,"identity":"f4b910a4-dfa7-460e-b142-d86caa1286d0","added_by":"auto","created_at":"2025-11-03 16:10:33","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1216946,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6560372/v1/1c74b86c-c431-4d40-8f67-406ab93229ec.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Pregnancy and Neonatal Outcomes in Women with Arcuate Uterus: A Population-Based Cohort Study of Over 3.8 Million Women","fulltext":[{"header":"BACKGROUND","content":"\u003cp\u003eCongenital uterine anomalies (CUAs) affect about 5% of women and are linked to adverse health outcomes [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. In non-pregnant women, CUAs can cause hematometra, hematocolpos, endometriosis, pelvic pain, abnormal uterine bleeding, and genital and urinary tract infections [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Additionally, 20\u0026ndash;30% of individuals with M\u0026uuml;llerian anomalies present with renal anomalies and other malformations, including cardiac defects [\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn pregnant women, CUAs increase the risk of first and second-trimester miscarriages, preterm delivery, malpresentation, cesarean section (CS), and small for gestational age (SGA) neonates [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Women with infertility also show higher rates of uterine malformations [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. These adverse outcomes are primarily associated with uterus didelphys, bicornuate uterus, and septate uterus [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe arcuate uterus, a common CUA, is characterized by a slight indentation of less than a centimeter at the fundus with an angle above 90 degrees [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Most women with an arcuate uterus are asymptomatic, often diagnosed incidentally during ultrasonography [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Compared to other CUAs, the arcuate uterus appears to have fewer adverse effects on pregnancies. For instance, Woelfer et al. reported a slight increase in second-trimester pregnancy losses and preterm labor among women with an arcuate uterus [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], while Mucowski et al. found no significant impact on reproductive outcomes in a smaller study [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eMost literature focuses on more significant uterine anomalies such as bicornuate or unicornuate uteri since arcuate uterus is often considered a variation of normal [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] or combines all CUAs. Studies specifically examining the effects of the arcuate uterus on pregnancy outcomes involved only a small number of participants, potentially lacking the power to detect significant differences. The largest study on this topic examined 420 cases of arcuate uterus and small septum combined [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Additionally, findings in the literature are conflicting. This study aims to clarify the pregnancy, delivery, and neonatal outcomes of women with an arcuate uterus using a large population database.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eData Source\u003c/h2\u003e \u003cp\u003e We conducted a retrospective population-based cohort study using data from the Health Care Cost and Utilization Project-Nationwide Inpatient Sample (HCUP-NIS) from 2010 to 2014. The HCUP-NIS database contains data on hospital inpatient stays and represents the largest publicly available all-payer inpatient database in the United States, covering over 97% of inpatient discharges from U.S. community hospitals. Data collection is managed by federal and state agencies, hospital associations, and private organizations. Data elements before 2015 are coded using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eStudy Population\u003c/h3\u003e\n\u003cp\u003eIn-hospital births occurring between 2010 and 2014 were included in the study. Births were identified using ICD-9-CM diagnostic codes (634x-679x, V22x, V23x, V27x) and procedural codes (72x-75x). Each pregnancy was included only once. In-hospital admissions resulting in delivery or maternal death were identified using specific ICD-9-CM codes (650x, 677x, 651x-676x) and procedural codes (72x, 73x, 74.0, 74.1, 74.2, 74.4, 74.99). Women with an arcuate uterus were identified using ICD-9-CM diagnostic code 752.36. Women without uterine anomalies served as the control group.\u003c/p\u003e\n\u003ch3\u003eData Collection\u003c/h3\u003e\n\u003cp\u003eBaseline characteristics recorded included age, race, type of insurance, income, body mass index (BMI) (obese BMI\u0026thinsp;\u0026ge;\u0026thinsp;30 kg/m\u0026sup2; versus non-obese BMI\u0026thinsp;\u0026lt;\u0026thinsp;30 kg/m\u0026sup2;), previous CS, smoking history, pre-existing hypertension, diabetes, thyroid disease, drug use, HIV status, use of in in vitro fertilization (IVF), and presence of multiple gestation.\u003c/p\u003e \u003cp\u003ePregnancy outcomes assessed included pregnancy-induced hypertension (PIH), chronic hypertension with superimposed preeclampsia, gestational hypertension, preeclampsia, eclampsia, gestational diabetes, and placenta previa. Delivery outcomes included preterm premature rupture of membranes (PPROM), preterm delivery, placental abruption, chorioamnionitis, mode of delivery (operative vaginal delivery, CS, spontaneous vaginal delivery (SVD)), hysterectomy, postpartum haemorrhage (PPH), wound complications, maternal death, blood transfusion, maternal infection, venous thromboembolism (VTE), and disseminated intravascular coagulopathy (DIC). Deep vein thrombosis (DVT) and pulmonary embolism (PE) were included under VTE. Neonatal outcomes included SGA, intrauterine fetal demise, and congenital anomalies.\u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eAn unmatched and a matched analysis were performed. Each case of arcuate uterus was matched to four controls based on age, race, income, and insurance type. Statistically significant differences in baseline characteristics between women with and without an arcuate uterus were compared using Chi-Squared or Fisher\u0026rsquo;s exact tests. Maternal and neonatal outcomes were compared using univariate and multivariate logistic regression analyses adjusted for confounding variables (characteristics with p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Analyses were conducted using SPSS 23.0 software. Statistical significance was set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"RESULTS","content":"\u003cp\u003eA total of 3,851,029 births occurred during the study period, including 754 from women with an arcuate uterus and 3,840,147 from women without CUAs (control group). Additionally, 10,128 births from women with other CUAs were excluded. The 754 births from women with an arcuate uterus were matched to 3,016 control births. The prevalence of arcuate uterus between 2010 and 2014 was 19.58 per 100,000 births, with a significant increase over time from 4.74 per 100,000 in 2010 to 31.68 per 100,000 in 2014 (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eBaseline Characteristics\u003c/h2\u003e \u003cp\u003eWomen with an arcuate uterus were more likely to be older than 25 years, Caucasian, in a higher income quartile, and have private insurance compared to the control group (all p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). They were also more likely to have had a previous CS (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), pre-gestational diabetes (p\u0026thinsp;=\u0026thinsp;0.03), thyroid disease (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), IVF pregnancies (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01), and multiple gestations (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01). In the matched group, women with an arcuate uterus were more likely to have had a previous CS (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and thyroid disease (p\u0026thinsp;=\u0026thinsp;0.02).\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 characteristics of the 3,840,901 births that occurred between 2004 to 2014\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eCharacteristics\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eArcuate Uterus\u003c/p\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;754\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo Arcuate Uterus\u003c/p\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;3,840,147\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003eAge (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e182 (24.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1379779 (35.8%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25\u0026ndash;34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e443 (58.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1894732 (49.3%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e128 (17.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e572637 (14.9%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003eRace\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"6\" rowspan=\"7\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWhite\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e534 (70.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2036437 (53.0%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBlack\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29 (3.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e560659 (14.6%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHispanic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e117 (15.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e825628 (21.5%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAsian and Pacific\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e42 (5.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20736 (5.4%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNative American\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5 (0.7%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e30721 (0.8%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOther\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28 (3.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e184327 (4.8%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003eIncome quartiles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLess than 39,000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e118 (15.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1063521 (27.7%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cspan\u003e$\u003c/span\u003e39,000\u0026ndash;47,999\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e167 (22.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e960037 (25.0%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cspan\u003e$\u003c/span\u003e48,000\u0026ndash;62,999\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e224 (29.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e967705 (25.2%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cspan\u003e$\u003c/span\u003e63,000 or more\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e245 (32.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e848589 (22.1%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003ePlan type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"6\" rowspan=\"7\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMedicare\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8 (1.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e26881 (0.7%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMedicaid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e191 (25.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1686081 (43.9%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePrivate including Health Maintenance Organizations\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e511 (67.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1911655 (49.8%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSelf-pay\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18 (2.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e99844 (2.6%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo charge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3840 (0.1%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOther\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e26 (3.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e111364 (2.9%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eObesity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e46 (6.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e211207 (5.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003ePrevious cesarean section\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e194 (25.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e656486 (17.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eSmoking during pregnancy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e41 (5.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e211207 (5.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.98\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eChronic hypertension\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16 (2.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e84483 (2.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.93\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003ePregestational diabetes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13 (1.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e38401 (1.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.03\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eDrug use\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (1.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e61442 (1.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.64\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eThyroid disease\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e48 (6.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e119045 (3.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eHIV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eIn vitro fertilization\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (0.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7680 (0.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.01\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eMultiple gestation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25 (3.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65282 (1.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.01\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\u003eHIV\u0026thinsp;=\u0026thinsp;Human immunodeficiency virus\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003ePregnancy Outcomes\u003c/h3\u003e\n\u003cp\u003ePregnancy outcomes in both matched and unmatched groups showed that women with an arcuate uterus had higher risks of PIH (adjusted odd ratio (aOR) 1.76, 95% CI 1.34\u0026ndash;2.32 in the matched group; aOR 1.32, 95% CI 1.03\u0026ndash;1.70 in the unmatched group) and preeclampsia (aOR 2.08, 95% CI 1.45\u0026ndash;2.98 in the matched group; aOR 1.63, 95% CI 1.18\u0026ndash;2.24 in the unmatched group) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). However, they were not at higher risk for gestational hypertension, eclampsia, chronic hypertension with superimposed preeclampsia, gestational diabetes, or placenta previa.\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\u003ePregnancy, delivery and other outcomes of the 3,840,901 births that occurred between 2010 to 2014\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eOutcomes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eArcuate uterus\u003c/p\u003e \u003cp\u003en\u0026thinsp;=\u0026thinsp;754\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo Arcuate Uterus\u003c/p\u003e \u003cp\u003en\u0026thinsp;=\u0026thinsp;3,840,147\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCrude Odds Ratio\u003c/p\u003e \u003cp\u003e(95% Confidence Interval)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAdjusted Odds Ratio (95% Confidence Interval)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eAdjusted\u003c/p\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e \u003cp\u003ePregnancy outcomes\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePregnancy induced HTN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e82 (10.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e307212 (8.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.40 (1.11\u0026ndash;1.76)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.32 (1.03\u0026ndash;1.70)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.03\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGestational HTN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30 (4.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e141085 (3.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.09 (0.76\u0026ndash;1.58)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.02 (0.70\u0026ndash;1.51)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.92\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePreeclampsia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e48 (6.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e145925 (3.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.72 (1.29\u0026ndash;2.31)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.63 (1.18\u0026ndash;2.24)\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\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEclampsia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (0.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3840 (0.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.94 (0.27\u0026ndash;13.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.55 (0.36\u0026ndash;18.12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.35\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePreeclampsia and Eclampsia superimposed HTN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (0.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23041 (0.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.25 (0.56\u0026ndash;2.80)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.22 (0.51\u0026ndash;2.96)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.66\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGDM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e57 (7.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e249609 (6.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.18 (0.90\u0026ndash;1.55)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.07 (0.80\u0026ndash;1.43)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.66\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePlacenta previa\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (0.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23041 (0.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.40 (0.63\u0026ndash;3.12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.11 (0.46\u0026ndash;2.69)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.81\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e \u003cp\u003eDelivery outcomes\u003csup\u003e\u0026Dagger;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePPROM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25 (3.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e42242 (1.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.96 (1.99\u0026ndash;4.41)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.86 (1.86\u0026ndash;4.40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePreterm delivery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e90 (11.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e253448 (6.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.92 (1.54\u0026ndash;2.40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.86 (1.45\u0026ndash;2.37)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAbruptio placenta\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22 (2.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e42242 (1.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.81 (1.84\u0026ndash;4.29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3.08 (1.99\u0026ndash;4.77)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eChorioamnionitis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16 (2.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e72963 (1.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.11 (0.67\u0026ndash;1.81)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.21 (0.71\u0026ndash;2.06)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.48\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOperative vaginal delivery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16 (1.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e180285 (4.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.25 (0.13\u0026ndash;0.47)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.26 (0.13\u0026ndash;0.52)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCesarean section\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e612 (81.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1255948 (32.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8.82 (7.35\u0026ndash;10.59)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e10.88 (8.90\u0026ndash;13.30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSpontaneous vaginal delivery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e133 (17.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2395092 (62.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.13 (0.11\u0026ndash;0.16)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.12 (0.10\u0026ndash;0.14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHysterectomy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3840 (0.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePPH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e32 (4.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e115204 (3.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.42 (0.99\u0026ndash;2.02)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.43 (0.99\u0026ndash;2.08)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.06\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWound complications\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (0.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11520 (0.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.81 (1.34\u0026ndash;5.92)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.14 (0.95\u0026ndash;4.78)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.07\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMaternal death\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTransfusion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (1.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e46082 (1.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.56 (0.92\u0026ndash;2.65)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.50 (0.84\u0026ndash;2.66)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.17\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e \u003cp\u003eOthers\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMaternal infection\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18 (2.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e88323 (2.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.05 (0.66\u0026ndash;1.68)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.18 (0.72\u0026ndash;1.94)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.52\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDVT\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePulmonary embolism\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (0.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e13.58 (3.38\u0026ndash;54.49)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e15.14 (3.76\u0026ndash;60.91)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eVTE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (0.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3840 (0.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.61 (1.15\u0026ndash;18.50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4.81 (1.20\u0026ndash;19.30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.03\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDIC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (0.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7680 (0.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.17 (0.81\u0026ndash;5.80)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.19 (0.82\u0026ndash;5.88)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003e\u003csup\u003e\u0026dagger;\u003c/sup\u003e Pregnancy outcomes: Adjusted for Age, Race, Plan types, Income quartiles, Previous cesarean section, Thyroid disease, Multiple gestation, Pregestational diabetes and IVF\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003e\u003csup\u003e\u0026Dagger;\u003c/sup\u003e Delivery outcomes: Adjusted for Age, Race, Plan types, Income quartiles, Previous cesarean section, Thyroid disease, Multiple gestation, Pregestational diabetes, IVF, Pregnancy induce hypertension and Preeclampsia\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003eHTN\u0026thinsp;=\u0026thinsp;hypertension; GDM\u0026thinsp;=\u0026thinsp;gestational diabetes mellitus; PPROM\u0026thinsp;=\u0026thinsp;premature rupture of membranes; PPH\u0026thinsp;=\u0026thinsp;post-partum hemorrhage; DVT\u0026thinsp;=\u0026thinsp;deep vein thrombosis; VTE\u0026thinsp;=\u0026thinsp;venous thromboembolism; DIC\u0026thinsp;=\u0026thinsp;disseminated intravascular coagulation\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003eDelivery Outcomes\u003c/h3\u003e\n\u003cp\u003eWomen with an arcuate uterus were more likely to experience PPROM (aOR 2.46, 95% CI 1.48\u0026ndash;4.09 in the matched group; aOR 2.86, 95% CI 1.86\u0026ndash;4.40 in the unmatched group), preterm delivery (aOR 2.74, 95% CI 2.06\u0026ndash;3.65 in the matched group; aOR 1.86, 95% CI 1.45\u0026ndash;2.37 in the unmatched group), and placental abruption (aOR 2.11, 95% CI 1.23\u0026ndash;3.63 in the matched group; aOR 3.08, 95% CI 1.99\u0026ndash;4.77 in the unmatched group) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). They also had significantly higher odds of delivering via CS (aOR 30.04, 95% CI 23.99\u0026ndash;37.63 in the matched group; aOR 10.88, 95% CI 8.90\u0026ndash;13.30 in the unmatched group) and were much less likely to have a spontaneous vaginal delivery (SVD) (aOR 0.04, 95% CI 0.03\u0026ndash;0.05 in the matched group; aOR 0.12, 95% CI 0.10\u0026ndash;0.14 in the unmatched group).\u003c/p\u003e \u003cp\u003eIn the matched cohort, women with an arcuate uterus had higher odds of PPH (aOR 1.67, 95% CI 1.09\u0026ndash;2.56), wound complications (aOR 3.42, 95% CI 1.18\u0026ndash;9.96), and DIC (aOR 5.58, 95% CI 1.21\u0026ndash;25.60). In the unmatched group, they had higher odds of VTE (aOR 4.81, 95% CI 1.20\u0026ndash;19.30) PE (aOR 15.14, 95% CI 3.76\u0026ndash;60.91). No maternal deaths were reported in either group, and no significant differences were found in other reported outcomes.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eNeonatal Outcomes\u003c/h2\u003e \u003cp\u003eDeliveries from women with an arcuate uterus had a 5.7% rate of SGA neonates compared to 3.2% in the matched control group (aOR 1.76, 95% CI 1.21\u0026ndash;2.56) and 2.6% in the unmatched control group (aOR 2.21, 95% CI 1.58\u0026ndash;3.10) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Rates of intrauterine fetal demise and congenital anomalies were similar between the groups in both the matched and unmatched cohorts.\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 of the 3,840,901 births that occurred between 2010 to 2014\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOutcomes\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eArcuate uterus\u003c/p\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;754\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNo Arcuate Uterus\u003c/p\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;3,840,147\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCrude Odds Ratio\u003c/p\u003e \u003cp\u003e(95% Confidence Interval)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAdjusted Odds Ratio\u003c/p\u003e \u003cp\u003e(95% Confidence Interval)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAdjusted\u003c/p\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\u003eSmall for gestational age\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e43 (5.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e99844 (2.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.30 (1.69\u0026ndash;3.13)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.21 (1.58\u0026ndash;3.10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntra uterine fetal demise\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (0.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15361 (0.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.59 (0.66\u0026ndash;3.83)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.97 (0.82\u0026ndash;4.75)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.13\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCongenital anomalies\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11520 (0.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e-\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 \u003csup\u003e\u0026dagger;\u003c/sup\u003e Neonatal outcomes: Adjusted for Age, Race, Plan type, Income quartiles, Previous cesarean section, Thyroid Disease, Multiple gestation, Pregestational diabetes, IVF, Pregnancy induced hypertension and Preeclampsia.\u003c/p\u003e \u003c/div\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThis large-scale, population-based study is the first to evaluate the impact of an arcuate uterus on obstetrical and neonatal outcomes using a substantial cohort. Our findings indicate that women with an arcuate uterus have higher risks of several complications, including PIH, preeclampsia, preterm delivery, PPROM, placental abruption, CS, PPH, and wound complications. Despite these increased risks, rates of intrauterine fetal demise and congenital anomalies were similar between women with and without an arcuate uterus. Additionally, deliveries in women with an arcuate uterus showed higher odds of SGA neonates.\u003c/p\u003e \u003cp\u003eThe arcuate uterus is one of the most common CUAs. The reported prevalence varies depending on the population studied and the mode of diagnosis. In a systematic review, Chan et al. demonstrated a prevalence of 3.9% of arcuate uterus in an unselected population [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. In studies estimating the prevalence of CUAs in women with fertility issues, the arcuate uterus was found in 12\u0026ndash;16% of that specific population [\u003cspan additionalcitationids=\"CR15\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Our results demonstrate a prevalence of an arcuate uterus of 19.58 per 100,000 births from 2010 to 2014. This lower number likely represents a low sensitivity for diagnosis of this anomaly but a high specificity of diagnosis in this database. Such a distribution should not compromise the results of this study. If anything, they may slightly underestimate the risks of the arcuate uterus in pregnancy. Our results also show a statistically significant increase in the incidence of the arcuate uterus over time, possibly due to increased detection and diagnosis over the years.\u003c/p\u003e \u003cp\u003eWomen with an arcuate uterus had a higher incidence of pregnancy-induced hypertension and preeclampsia. Not many studies have specifically looked at this outcome in CUAs. Fox et al. described the possibility of unilateral placental implantation and functional exclusion of one of the uterine arteries as potential causes for increased rates of intrauterine growth restriction and preeclampsia in women with major uterine anomalies. In their study, the arcuate uterus did not seem to be associated with increased preeclampsia; however, they had only 14 cases with the malformation, which might not have provided enough power to detect the risk of preeclampsia [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. It is thus unclear if the arcuate uterus could also lead to abnormal placentation and possible hypertensive disorders during pregnancy.\u003c/p\u003e \u003cp\u003eAs demonstrated by others, the arcuate uterus was also associated with thirty times the rates of CS delivery and lower rates of spontaneous vaginal delivery. This could be explained by the fact that malpresentations and placental abruption are more common [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Thus, it is not surprising that these women were more likely to have had CS in the past. Higher rates of CS and the associated coagulopathy, as well as the possible higher risk of hypertensive disorders in pregnancy, could directly explain why women with an arcuate uterus had a higher risk of postpartum hemorrhage and five times more DIC. This increase in the risk of postpartum hemorrhage and DIC was only found in the matched cohort. In the unmatched cohort, women with an arcuate uterus had twelve times more PE and five times more deep vein thrombosis events. This difference was not found once the cases were matched to controls. The increased risk of DIC noted in our results might not, however, be significant, as only a very small number of women suffered from these outcomes. It is unlikely that the arcuate uterus itself would cause an increased risk of coagulability.\u003c/p\u003e \u003cp\u003eIn our study, women with an arcuate uterus demonstrated about twice the risk for PPROM, preterm delivery, and SGA. Most of the published literature recognizes these risks with CUAs as a whole but not necessarily with the arcuate uterus [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Lekovich et al. suggested placental malperfusion as a possible cause of preterm delivery in women with uterine anomalies. Placental malperfusion is also a recognized cause of small neonates [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Woelfer et al. and Fox et al. found that women with an arcuate uterus had higher rates of second-trimester miscarriage and preterm delivery compared to those with a normal uterus. Their respective study populations included 72 and 14 women with the anomaly [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. However, a systematic review of 12 articles looking partly at the outcomes of the arcuate uterus did not find any of these differences, although the relative risk was marginally insignificant at 2.04 (95% CI 0.99 to 4.1) [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Our larger cohort might have provided sufficient power to confirm that the arcuate uterus is indeed associated with risks of PPROM, preterm delivery, and SGA.\u003c/p\u003e \u003cp\u003eWhether metroplasty of the arcuate uterus improves pregnancy outcomes is controversial. One prospective study of 96 women with arcuate and septate uteri found no difference in outcomes [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Conversely, a larger retrospective study of 420 small septums and arcuate uteri reported a decrease in the rate of preterm birth from 34% before hysteroscopic resection to 7% after, and a decrease in the rate of extreme preterm birth from 13\u0026ndash;3% [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eA recent case-control study by also looked at the pregnancy outcomes of 37 women with an arcuate uterus compared to 165 women with similar baseline characteristics and no congenital uterine anomalies. Similar to our study, their results showed that women with an arcuate uterus were at increased risk of spontaneous preterm birth and had lower mean birthweight. However, there were no differences in the risks of preeclampsia or CS [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe study has limitations, such as its retrospective nature and reliance on ICD-9-CM codes for identifying arcuate uterus cases, which might introduce classification bias. Additionally, the database lacks detailed clinical data on the method of diagnosis and severity of the arcuate uterus, potentially influencing pregnancy outcomes. This raises the possibility that some cases might have been misclassified, including women with a low-level septate uterus rather than an arcuate uterus, introducing further bias into our findings. Moreover, the database lacks information on various confounding factors, such as fertility status (partially inferred from IVF use), previous pregnancy losses, parity, indications for cesarean section, history of coagulopathies, and previous adverse pregnancy or neonatal outcomes. These gaps limit our ability to fully account for all variables that might influence the observed outcomes, although these complications could directly result from the presence of an arcuate uterus itself.\u003c/p\u003e \u003cp\u003eThe strengths of this study include its large cohort size, making it the most extensive study to date examining pregnancy, delivery, and neonatal outcomes associated with the arcuate uterus. The study design involved matching cases of arcuate uterus to controls, and we adjusted for confounding variables using multivariate logistic regression analysis. This robust methodology enhances confidence in our findings despite the heterogeneity in the existing literature.\u003c/p\u003e \u003cp\u003eAdditionally, even if some subjects had low-level septate uteri rather than truly arcuate uteri, the results likely reflect the complications in the population diagnosed with arcuate uteri. We expect the rate of misdiagnosis to be consistent between our study and the general population, thereby supporting the generalizability of our findings. Consequently, our results provide valuable insights that can guide practitioners in understanding and managing the pregnancy risks associated with an arcuate uterus.\u003c/p\u003e"},{"header":"CONCLUSIONS","content":"\u003cp\u003eWomen with an arcuate uterus are at significantly increased risk for several adverse pregnancy outcomes, including PIH, preeclampsia, PPROM, preterm delivery, placental abruption, CS, PPH, DIC, SGA neonates, and wound complications. These findings highlight the importance of targeted monitoring and management strategies for this population. Our results differ from those of some smaller cohorts. Therefore, further large-scale studies are needed to confirm these findings and to develop effective interventions to improve pregnancy outcomes for women with an arcuate uterus.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eCUAs: Congenital uterine anomalies; CS: Cesarean section; SGA: Small for gestational age; HCUP-NIS: Project-Nationwide Inpatient Sample; ICD-9-CM: International Classification of Diseases, Ninth Revision, Clinical Modification; BMI: Body mass index; IVF: In vitro fertilization; PIH: Pregnancy-induced hypertension; PPROM: Preterm premature rupture of membranes; SVD: Spontaneous vaginal delivery; PPH: Postpartum haemorrhage; VTE: Venous thromboembolism; DIC: Disseminated intravascular coagulopathy; DVT: Deep vein thrombosis; PE: Pulmonary embolism; aOR: Adjusted odd ratio; CI: Confidence interval\u0026nbsp;\u003c/p\u003e\n"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study used de-identified, publicly available data and was conducted in accordance with the ethical standards of the Tri-Council Policy Statement: Ethical Conduct for Research Involving Humans (TCPS 2, 2010) and the principles of the Declaration of Helsinki. Institutional review board approval was not required. Informed consent was not applicable due to the retrospective nature of the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe dataset supporting the conclusions of this article is available in the Health Care Cost and Utilization Project-Nationwide Inpatient Sample (HCUP-NIS) repository, https://health.gov/healthypeople/objectives-and-data/data-sources-and-methods/data-sources/healthcare-cost-and-utilization-project-national-nationwide-inpatient-sample-hcup-nis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNK, \u0026nbsp;EMG, MHD contributed in conception, design and drafting of the\u003c/p\u003e\n\u003cp\u003emanuscript. NK, EMG, AB, HB, and MHD contributed in data collection, analysis and interpretation of data. All authors reviewed and approved the final version for submission.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eChan YY, Jayaprakasan K, Zamora J, Thornton JG, Raine-Fenning N, Coomarasamy A. The prevalence of congenital uterine anomalies in unselected and high-risk populations: a systematic review. Hum Reprod Update. 2011;17:761\u0026ndash;71.\u003c/li\u003e\n\u003cli\u003eManagement of acute obstructive uterovaginal anomalies: ACOG committee opinion, number 779. Obstet Gynecol. 2019;133:e363\u0026ndash;71.\u003c/li\u003e\n\u003cli\u003eLin PC, Bhatnagar KP, Nettleton GS, Nakajima ST. Female genital anomalies affecting reproduction. Fertil Steril. 2002;78:899\u0026ndash;915.\u003c/li\u003e\n\u003cli\u003eOppelt P, von Have M, Paulsen M, Strissel PL, Strick R, Brucker S, et al. Female genital malformations and their associated abnormalities. Fertil Steril. 2007;87:335\u0026ndash;42.\u003c/li\u003e\n\u003cli\u003ePittock ST, Babovic-Vuksanovic D, Lteif A. Mayer-Rokitansky-K\u0026uuml;ster-Hauser anomaly and its associated malformations. Am J Med Genet A. 2005;135:314\u0026ndash;6.\u003c/li\u003e\n\u003cli\u003eFox NS, Roman AS, Stern EM, Gerber RS, Saltzman DH, Rebarber A. Type of congenital uterine anomaly and adverse pregnancy outcomes. J Matern Fetal Neonatal Med. 2014;27:949\u0026ndash;53.\u003c/li\u003e\n\u003cli\u003eHua M, Odibo AO, Longman RE, Macones GA, Roehl KA, Cahill AG. Congenital uterine anomalies and adverse pregnancy outcomes. Am J Obstet Gynecol. 2011;205:558.e1-5.\u003c/li\u003e\n\u003cli\u003eHassan M-AM, Lavery SA, Trew GH. Congenital uterine anomalies and their impact on fertility. Womens Health (Lond Engl). 2010;6:443\u0026ndash;61.\u003c/li\u003e\n\u003cli\u003eLudwin A, Martins WP, Nastri CO, Ludwin I, Coelho Neto MA, Leit\u0026atilde;o VM, et al. Congenital Uterine Malformation by Experts (CUME): better criteria for distinguishing between normal/arcuate and septate uterus? Ultrasound Obstet Gynecol .2018;51(1):101\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eJayaprakasan K, Ojha K. Diagnosis of congenital uterine abnormalities: practical considerations. J Clin Med. 2022;11(5).\u003c/li\u003e\n\u003cli\u003eWoelfer B, Salim R, Banerjee S, Elson J, Regan L, Jurkovic D. Reproductive outcomes in women with congenital uterine anomalies detected by three-dimensional ultrasound screening. Obstet Gynecol. 2001;98(6):1099\u0026ndash;103.\u003c/li\u003e\n\u003cli\u003eMucowski SJ, Herndon CN, Rosen MP. The arcuate uterine anomaly: a critical appraisal of its diagnostic and clinical relevance. Obstet Gynecol Surv. 2010;65(7):449\u0026ndash;54.\u003c/li\u003e\n\u003cli\u003eTomazevic T, Ban-Frangez H, Ribic-Pucelj M, Premru-Srsen T, Verdenik I. Small uterine septum is an important risk variable for preterm birth. Eur J Obstet Gynecol Reprod Biol. 2007;135(2):154\u0026ndash;7.\u003c/li\u003e\n\u003cli\u003eZhang Y, Zhao Y, Qiao J. Obstetric outcome of women with uterine anomalies in China. Chin Med J. 2010;123(4):418\u0026ndash;22.\u003c/li\u003e\n\u003cli\u003eJayaprakasan K, Chan YY, Sur S, Deb S, Clewes JS, Raine-Fenning NJ. Prevalence of uterine anomalies and their impact on early pregnancy in women conceiving after assisted reproduction treatment. Ultrasound Obstet Gynecol. 2011;37(6):727\u0026ndash;32.\u003c/li\u003e\n\u003cli\u003ePrior M, Richardson A, Asif S, Polanski L, Parris-Larkin M, Chandler J, et al. Outcome of assisted reproduction in women with congenital uterine anomalies: a prospective observational study. Ultrasound Obstet Gynecol. 2018;51(1):110\u0026ndash;7.\u003c/li\u003e\n\u003cli\u003eŻyła MM, Wilczyński J, Nowakowska-Głąb A, Maniecka-Bryła I, Nowakowska D. Pregnancy and Delivery in Women with Uterine Malformations. Adv Clin Exp Med. 2015;24(5):873\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eLekovich J, Stewart J, Anderson S, Niemasik E, Pereira N, Chasen S. Placental malperfusion as a possible mechanism of preterm birth in patients with M\u0026uuml;llerian anomalies. J Perinat Med. 2017;45(1):45\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eSaravelos SH, Cocksedge KA, Li T-C. The pattern of pregnancy loss in women with congenital uterine anomalies and recurrent miscarriage. Reprod Biomed Online. 2010;20(3):416\u0026ndash;22.\u003c/li\u003e\n\u003cli\u003eCarbonnel M, Pirtea P, de Ziegler D, Ayoubi JM. Uterine factors in recurrent pregnancy losses. Fertil Steril. 2021;115(3):538\u0026ndash;45.\u003c/li\u003e\n\u003cli\u003eVenetis CA, Papadopoulos SP, Campo R, Gordts S, Tarlatzis BC, Grimbizis GF. Clinical implications of congenital uterine anomalies: a meta-analysis of comparative studies. Reprod Biomed Online. 2014;29(6):665\u0026ndash;83.\u003c/li\u003e\n\u003cli\u003eGergolet M, Campo R, Verdenik I, Kenda Suster N, Gordts S, Gianaroli L. No clinical relevance of the height of fundal indentation in subseptate or arcuate uterus: a prospective study. Reprod Biomed Online. 2012;24(5):576\u0026ndash;82.\u003c/li\u003e\n\u003cli\u003eConnolly CT, Hill MB, Klahr RA, Zafman KB, Rebarber A, Fox NS. Arcuate uterus as an independent risk factor for adverse pregnancy outcomes. Am J Perinatol. 2024;41(2):167\u0026ndash;73. \u003c/li\u003e\n\u003c/ol\u003e\n"}],"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":"[email protected]","identity":"bmc-pregnancy-and-childbirth","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"prch","sideBox":"Learn more about [BMC Pregnancy and Childbirth](http://bmcpregnancychildbirth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/prch/default.aspx","title":"BMC Pregnancy and Childbirth","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"arcuate uterus, cohort studies, pregnancy complications, pregnancy outcome, uterine anomalies","lastPublishedDoi":"10.21203/rs.3.rs-6560372/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6560372/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003eCongenital uterine anomalies are associated with adverse reproductive outcomes, yet the impact of the arcuate uterus remains unclear due to limited sample sizes and inconsistent findings in previous studies. We utilized a large population database to assess pregnancy, delivery, and neonatal outcomes in women with an arcuate uterus.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eRetrospective population-based study using data from the Health Care Cost and Utilization Project-Nationwide Inpatient Sample. Cases of arcuate uterus were identified using ICD code 752.36. Pregnancies in women with an arcuate uterus were matched to 3,016 pregnancies in women without congenital uterine anomalies (1 to 4) and compared to the entire population without congenital anomalies. Multivariate logistic regression adjusted for confounding variables.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eAmong 3,841,147 control births and 754 births in women with an arcuate uterus, more of these women were older than 25 and had higher rates of previous cesarean sections (CS), in-vitro pregnancies, and multiple gestations (all P\u0026lt;0.01). Pregnancy outcomes showed higher rates of pregnancy-induced hypertension (adjusted odds ratio (aOR) 1.32), preeclampsia (aOR 1.63), premature preterm rupture of membranes (aOR 2.86), preterm delivery (aOR 1.86), placental abruption (aOR 3.08), CS (aOR 10.88), and small for gestational age (SGA) neonates (aOR 2.21) (all 95%CI excluding 1).\u003c/p\u003e\n\u003cp\u003eCompared to the matched cohort, women with an arcuate uterus had higher rates of pregnancy-induced hypertension (aOR 1.76), preeclampsia (aOR 2.08), premature preterm rupture of membranes (aOR 2.46), preterm delivery (aOR 2.74), placental abruption (aOR 2.11), postpartum hemorrhage (aOR 1.67), wound complications (aOR 3.42), CS (aOR 30.04), disseminated intravascular coagulopathy (DIC) (aOR 5.36), and SGA (aOR 1.76) (all 95%CI excluding 1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions: \u003c/strong\u003eWomen with an arcuate uterus are at increased risk of adverse pregnancy outcomes, particularly CS and DIC. Enhanced surveillance and preventive measures are recommended.\u003c/p\u003e","manuscriptTitle":"Pregnancy and Neonatal Outcomes in Women with Arcuate Uterus: A Population-Based Cohort Study of Over 3.8 Million Women","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-30 06:23:23","doi":"10.21203/rs.3.rs-6560372/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-08-11T14:24:32+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-27T23:34:23+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-15T19:43:29+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"69916559383253759595269139125252412968","date":"2025-06-09T16:11:29+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"245932036691340164820002749009299498557","date":"2025-06-09T14:52:33+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"272828532165367753342167267737052611188","date":"2025-06-03T11:47:23+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-05-28T07:45:57+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-05-05T20:48:37+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-02T04:15:29+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-02T04:13:54+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Pregnancy and Childbirth","date":"2025-04-30T02:27:37+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-pregnancy-and-childbirth","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"prch","sideBox":"Learn more about [BMC Pregnancy and Childbirth](http://bmcpregnancychildbirth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/prch/default.aspx","title":"BMC Pregnancy and Childbirth","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"9bdd49c4-1d02-4bbd-a4cb-43b2016f6948","owner":[],"postedDate":"May 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-11-03T16:07:59+00:00","versionOfRecord":{"articleIdentity":"rs-6560372","link":"https://doi.org/10.1186/s12884-025-08125-7","journal":{"identity":"bmc-pregnancy-and-childbirth","isVorOnly":false,"title":"BMC Pregnancy and Childbirth"},"publishedOn":"2025-10-28 15:58:34","publishedOnDateReadable":"October 28th, 2025"},"versionCreatedAt":"2025-05-30 06:23:23","video":"","vorDoi":"10.1186/s12884-025-08125-7","vorDoiUrl":"https://doi.org/10.1186/s12884-025-08125-7","workflowStages":[]},"version":"v1","identity":"rs-6560372","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6560372","identity":"rs-6560372","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}