The U-Shaped Relationship Between Pregnancy Physical Activity and Neonatal Birth Weight

The U-Shaped Relationship Between Pregnancy Physical Activity and Neonatal Birth Weight | 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 Article The U-Shaped Relationship Between Pregnancy Physical Activity and Neonatal Birth Weight Shuqun Ren, Xiaohong You, Qian Zhao, Lin-lin Jiang, Aihong Jin This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7350562/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract This study prospectively analyzed the relationship between physical activity during pregnancy and neonatal birth weight in 337 singleton pregnant women in Shenzhen, China. The participants were enrolled from May to October 2023 at the Shenzhen Second People's Hospital, where they underwent routine prenatal check-ups and deliveries. The physical activity during pregnancy was assessed three times using the Pregnancy Physical Activity Questionnaire (PPAQ) at three different stages: mid-pregnancy (T1), late pregnancy (T2, preterm), and late pregnancy (T3, full-term).After adjusting for confounding factors using generalized additive models (GAM) and smooth curve fitting, a U-shaped relationship was observed between physical activity during pregnancy and neonatal birth weight. When physical activity exceeded 218.22 MET-h•wk − 1 , each standard deviation increase in physical activity was associated with a 544.04g increase in birth weight (β: 544.04, 95% CI: 184.77 to 903.32, P = 0.0032). No significant association was found below this threshold. The results suggest that moderate to higher levels of physical activity during late pregnancy are beneficial for fetal weight gain, whereas both low and excessively high levels may be detrimental. Clinically, individualized and balanced physical activity prescriptions during pregnancy should be developed. Health sciences/Diseases Health sciences/Health care Health sciences/Medical research Health sciences/Risk factors Physical activity Pregnancy Birthweight U-shaped relationship Figures Figure 1 Figure 2 Introduction Neonatal birth weight (BW) is an important indicator of fetal intrauterine development and is closely associated with metabolic health during childhood and even adulthood [ 1 , 2 ] . Lower birth weight is associated with an increased risk of chronic diseases such as obesity, diabetes, and hypertension in adulthood [ 3 , 4 ] . High birth weight, also known as macrosomia, is associated with an increased risk of metabolic syndrome, cardiovascular diseases, and other health issues in adulthood [ 5 – 7 ] . Studies have shown that birth weight can influence insulin resistance, blood glucose, and lipid levels. For each 100-gram decrease in birth weight of full-term newborns, the incidence of insulin resistance and dyslipidemia in childhood significantly increases [ 8 , 9 ] .However, birth weight not only impacts health through the weight itself but also exacerbates the risk of chronic diseases by influencing organ development and the early programming of metabolic systems [ 10 , 11 ] . Physical activity (PA) during pregnancy, as one of the most practical and scalable lifestyle interventions, has been shown to reduce the risk of pregnancy complications and adverse birth outcomes. Therefore, it is widely recommended as a proactive health behavior to improve pregnancy outcomes [ 12 , 13 ] .The World Health Organization's 2020 Guidelines on Physical Activity and Sedentary Behaviour recommend that all pregnant women without medical contraindications engage in at least 150 to 300 minutes of moderate-intensity aerobic activity per week, combined with strength training, to achieve dual health benefits for both mother and baby [ 14 ] .In the same year, the American College of Obstetricians and Gynecologists (ACOG) issued Committee Opinion No. 804, which stated that regular physical activity does not increase the risk of miscarriage, preterm birth, low birth weight, or macrosomia. It encourages healthy pregnant women to maintain or begin an exercise regimen following a safety assessment [ 15 ] . However, the impact of PA on BW remains a topic of significant debate. A 2023 systematic review and meta-analysis involving 16,524 pregnant women showed that prenatal exercise interventions did not significantly affect birth weight (BW), but they were associated with a 21% reduction in the risk of macrosomia [ 16 ] . A study by Maíra B. Malta et al. found that at least 150 minutes of leisure-time physical activity per week during late pregnancy was negatively associated with offspring birth weight [ 17 ] . Potential reasons for the discrepancy in results include variations in the dosage of physical activity during pregnancy, differences in baseline BMI among pregnant women, and the presence of pregnancy-related complications. Moreover, existing studies primarily focus on populations from Europe and North America, while Asian pregnant women exhibit significant differences in physical activity patterns, dietary structure, and placental physiology, limiting the extrapolation of these findings. Therefore, this study focuses on Chinese pregnant women to observe the relationship between physical activity during pregnancy and neonatal birth weight, providing scientific evidence for the development of precise prenatal exercise prescriptions to improve maternal and neonatal outcomes. Materials and Methods Study design and participants This study is a prospective cohort study. We recruited primiparous pregnant women who underwent routine prenatal check-ups at the Obstetrics Outpatient Department and delivered at the Obstetrics Ward of Shenzhen Second People's Hospital between May 2023 and October 2023. The women were enrolled into the prospective cohort during their mid-pregnancy (T1, 14–27 weeks) when they completed the first physical activity survey. The second survey was conducted during late pregnancy, preterm (T2, 28 + 6 to 32 weeks), and the third survey took place during late pregnancy, full-term (T3, 33 weeks to delivery), with continuous follow-up until delivery. Inclusion criteria: ① Age ≥ 20 years; ② Singleton pregnancy; ③ No mental or cognitive impairments, able to effectively communicate with the researchers or complete the questionnaire independently; ④ Voluntary participation and signing of informed consent; ⑤ Good physical health prior to pregnancy, with no history of diabetes, hypertension, heart disease, or other related conditions. Exclusion criteria: ① Pregnancy complications such as placenta previa or threatened miscarriage;② Severe complications such as peripartum cardiomyopathy, liver diseases, or hematologic disorders during pregnancy; ③ A history of psychological or psychiatric disorders. Exclusion criteria for data: ① Inaccurate questionnaire responses; ② Incomplete data that could impact the analysis of research outcomes. This study was approved by the Ethics Committee of Shenzhen Second People's Hospital (Ethics Approval No.: 2023-015-02PJ). Exposure The exposure variable in this study is physical activity during late pregnancy, which was assessed using the Pregnancy Physical Activity Questionnaire (PPAQ). The results were recorded as continuous variables. The PPAQ was developed by American scholars, and the Chinese version of the PPAQ was adapted by Chinese researchers in 2012 to better suit the local context. The test-retest reliability of the Chinese version is 0.944, and its content validity is 0.940, demonstrating good reliability and validity. It is also significantly correlated with energy expenditure (r = 0.768, P < 0.001). The questionnaire classifies physical activity by type and intensity, addressing the issue of low differentiation between different types of physical activity. It has been widely used for assessing physical activity levels during pregnancy. The Chinese version of the PPAQ includes four dimensions and 31 items: 13 items on household activities, 5 items on transportation, 8 items on recreational exercise, and 5 items on occupational activities. Physical activities are categorized based on intensity, with energy expenditure values referenced from the physical activity guidelines and expressed as metabolic equivalents (MET). Each item includes six options, each corresponding to a different weight coefficient. These are then multiplied by the corresponding energy expenditure values to calculate the weekly energy expenditure (MET-h•wk − 1 ) for that activity. According to the ACOG recommendations, physical activity with an energy expenditure of ≥ 7.5 MET-h•wk − 1 per week is classified as meeting the recommended level of physical activity during pregnancy, while < 7.5 MET-h•wk − 1 is considered insufficient. Outcomes The primary outcome was BW (grams). BW was measured by the delivery room nurse as soon as possible after delivery (with the newborn undressed and unwrapped), using a calibrated electronic baby scale. The reading was accurate to 10 g and recorded in the delivery record. If multiple measurements were taken during the same delivery, the first valid measurement was used. To ensure data quality, we conducted consistency checks on the weight records: when significant discrepancies or missing data were found, medical records were reviewed and cross-checked with the delivery records. Inconsistent data were corrected or excluded. Statistical analysis Continuous variables are expressed as mean ± standard deviation (SD) for normally distributed data or median (interquartile range, IQR) for skewed data, and categorical variables are presented as frequencies or percentages. For normally distributed continuous variables, one-way analysis of variance (ANOVA) was used; for skewed distributions, the Kruskal-Wallis H test was applied. Chi-square tests were used for group comparisons of categorical variables. Baseline characteristics were compared between the groups, with PA during pregnancy classified based on the ACOG recommendation. PA with energy expenditure ≥ 7.5 MET-h•wk − 1 was classified as active, and < 7.5 MET-h•wk − 1 as inactive [ 15 ] . Univariate analysis was performed using linear regression to evaluate the relationship between PA during pregnancy and BW. Results are presented as regression coefficients with 95% confidence intervals (CIs). To standardize the comparison, PA during pregnancy data were first standardized by calculating Z-scores, and regression coefficients were estimated for each standard deviation increase in physical activity. Multivariate analysis was performed using binary logistic regression, constructing three distinct models: the unadjusted model (without any covariate adjustment), the minimally adjusted model (adjusted for sociodemographic variables only), and the fully adjusted model (adjusted for all relevant covariates, as shown in Table 3). Covariates with variance inflation factors (VIFs) greater than 10 were removed from the fully adjusted model. Considering the potential non-linear relationship between PA during pregnancy and BW, smooth curve fitting (penalized spline method) was used to address non-linearity. A two-piecewise linear regression model was used to examine the saturation effect of PA during pregnancy on neonatal birth weight. The inflection point for PA was determined through exploratory analysis, where the trial inflection point was moved along a predefined interval to identify the point that maximized model likelihood. A log-likelihood ratio test was performed to compare the one-line linear regression model with the two-piecewise linear regression model. To assess the robustness of the findings, sensitivity analysis was conducted by excluding pregnant women with gestational diabetes. The analysis focused on the normal pregnancy group, evaluating the impact of PA on neonatal birth weight in the absence of gestational diabetes. This analysis verified the potential influence of gestational diabetes on the conclusions. All statistical analyses were performed using R software ( http://www.R-project.org , The R Foundation) and EmpowerStats software ( http://www.empowerstats.com , X&Y Solutions, Inc., Boston, MA, USA). A two-sided P-value of < 0.05 was considered statistically significant. Results Baseline characteristics of nulliparous patients This study included 360 pregnant women who attended regular prenatal check-ups at Shenzhen Second People's Hospital from May 2023 to October 2023. 5 cases were excluded due to absolute contraindications for physical activity (placenta previa), 5 cases were excluded due to pregnancy-induced hypertension, 3 cases were excluded due to pregnancy-associated arrhythmia, and 10 cases were excluded due to missing or erroneous physical activity data. A total of 337 pregnant women completed the survey. Details of the process can be found in the flowchart ( Fig. 1 ) . The participants were divided into two groups based on whether they met the recommended level of PA during pregnancy. The mean age of the 337 women was 31.26 ± 4.07 years. The mean BW was 3195.80 ± 403.60g. The characteristics of the mothers and newborns are shown in Table 1 . Table 1 Baseline Data of Pregnant Women by Physical Activity Level and Neonatal Birth Weight T1 P Value T2 P Value T3 P Value Inactive (n = 194) Active (n = 143) Inactive (n = 232) Active (n = 105) Inactive (n = 215) Active (n = 122) Maternal age, y 31.06 ± 4.20 31.54 ± 3.89 0.334 31.13 ± 4.13 31.54 ± 3.93 0.394 31.49 ± 4.17 30.86 ± 3.87 0.173 BMI (kg/m 2 ) 21.46 ± 3.18 21.59 ± 3.03 0.714 21.60 ± 3.18 21.33 ± 2.97 0.464 21.40 ± 3.20 21.72 ± 2.96 0.358 GA weeks at delivery (wk) 38.94 ± 1.16 39.09 ± 1.04 0.222 38.96 ± 1.16 39.10 ± 0.99 0.293 38.86 ± 1.10 39.26 ± 1.07 0.001 Weight gain, g 13.52 ± 10.57 14.13 ± 10.51 0.599 13.29 ± 9.19 14.87 ± 13.00 0.202 13.33 ± 9.99 14.57 ± 11.43 0.300 Birthweight, g 3163.38 ± 409.00 3240.11 ± 393.22 0.085 3172.51 ± 398.17 3247.05 ± 412.61 0.117 3172.31 ± 380.75 3237.01 ± 439.45 0.158 Birth length, cm 49.33 ± 1.75 49.09 ± 4.49 0.485 49.06 ± 3.67 49.61 ± 1.76 0.140 49.04 ± 3.76 49.57 ± 1.82 0.147 head circumference, cm 33.26 ± 1.24 33.48 ± 1.21 0.099 33.36 ± 1.27 33.33 ± 1.16 0.847 33.43 ± 1.23 33.22 ± 1.24 0.141 Educational Level 0.013 0.021 0.678 High School and Below 32 (16.49%) 12 (8.45%) 37 (16.02%) 7 (6.67%) 30 (14.02%) 14 (11.48%) Associate's or Bachelor's Degree 150 (77.32%) 111 (78.17%) 177(76.62%) 84 (80.00%) 163 (76.17%) 98 (80.33%) Graduate Degree and Above 12 (6.19%) 19 (13.38%) 17 (7.36%) 14 (13.33%) 21 (9.81%) 10 (8.20%) Profession 0.487 0.736 0.493 Unemployed 38 (19.59%) 35 (24.65%) 53 (22.94%) 20 (19.05%) 50 (23.37%) 23 (18.85%) Corporate Employee 126 (64.95%) 89 (62.68%) 144(62.34%) 71 (67.62%) 131 (61.21%) 84 (68.85%) Government Employee 30 (15.46%) 18 (12.68%) 34 (14.72%) 14 (13.33%) 33 (15.42%) 15 (12.30%) Average Monthly Household Income Per Capita ( Yuan) 0.038 0.126 0.173 < 10000 67 (34.54%) 31 (21.83%) 75 (32.47%) 23 (21.90%) 69 (32.24%) 29 (23.77%) 10000 ~ 20000 76 (39.18%) 64 (45.07%) 90 (38.96%) 50 (47.62%) 82 (38.32%) 58 (47.54%) ≥ 20000 51 (26.29%) 47 (33.10%) 66 (28.57%) 32 (30.48%) 63 (29.44%) 35 (28.69%) Pregnancy Intention 0.929 0.962 0.646 Planned 133 (68.56%) 98 (69.01%) 159 (68.83%) 72 (68.57%) 149 (69.63%) 82 (67.21%) Unplanned 61 (31.44%) 44 (30.99%) 72 (31.17%) 33 (31.43%) 65 (30.37%) 40 (32.79%) Number of pregnancy 0.260 0.422 0.139 1 84 (43.30%) 71 (50.00%) 101 (43.72%) 54 (51.43%) 90 (42.06%) 65 (53.28%) 2 48 (24.74%) 37 (26.06%) 61 (26.41%) 24 (22.86%) 58 (27.10%) 27 (22.13%) ≥ 3 62 (31.96%) 34 (23.94%) 69 (29.87%) 27 (25.71%) 66 (30.84%) 30 (24.59%) Number of Births 0.058 0.078 0.225 0 119 (61.34%) 98 (69.01%) 142 (61.47%) 75 (71.43%) 131 (61.21%) 86 (70.49%) 1 60 (30.93%) 41 (28.87%) 73 (31.60%) 28 (26.67%) 70 (32.71%) 31 (25.41%) ≥ 2 15 (7.73%) 3 (2.11%) 16 (6.93%) 2 (1.90%) 13 (6.07%) 5 (4.10%) Delivery way 0.841 0.090 0.001 Vaginal delivery 125 (64.43%) 93 (65.49%) 143 (61.90%) 75 (71.43%) 124 (57.94%) 94 (77.05%) Cesarean delivery 69 (35.57%) 49 (34.51%) 88 (38.10%) 30 (28.57%) 90 (42.06%) 28 (22.95%) Newborn Gender 0.439 0.565 0.695 Male 108 (55.67%) 73 (51.41%) 122 (52.81%) 59 (56.19%) 117 (54.67%) 64 (52.46%) Female 86 (44.33%) 69 (48.59%) 109 (47.19%) 46 (43.81%) 97 (45.33%) 58 (47.54%) Anemia 0.709 0.326 0.572 No 80 (41.24%) 58 (40.85%) 92 (39.83%) 46 (43.81%) 87 (40.65%) 51 (41.80%) Mild 60 (30.93%) 43 (30.28%) 70 (30.30%) 33 (31.43%) 65 (30.37%) 38 (31.15%) Moderate 54 (27.84%) 41 (28.87%) 69 (29.87%) 25 (24.76%) 62 (28.97%) 33 (27.05%) Univariate Analysis of the BW Univariate analysis (Table S1) showed that pre-pregnancy BMI, gestational weight gain, education level, occupation, anemia, number of deliveries, gestational age at delivery, neonatal sex, and neonatal head circumference and length were associated with neonatal birth weight (P < 0.05). Results of nonlinear association between PA during pregnancy and BW Non-linear associations between physical activity during pregnancy (PA) and the duration of the first stage of labor were observed through smooth curve fitting and generalized additive models. Our results indicate that after adjusting for age, education level, occupation, household per capita monthly income, number of deliveries, pre-pregnancy BMI, gestational weight gain, and gestational age at delivery, the relationship between PA during pregnancy in T2 and BW exhibited a threshold effect. The inflection point was identified at 218.22 MET-h•wk^-1. When PA during pregnancy exceeded 218.22 MET-h•wk^-1, each standard deviation increase in PA was associated with an increase in BW of 544.04g (β: 544.04, 95% CI: 184.77 to 903.32, P = 0.0032). However, when PA during pregnancy was below 218.22 MET-h•wk^-1, BW did not change with increasing PA (β: -12.92, 95% CI: -60.25 to 34.42, P = 0.5931) ( Fig. 2 and Table 2 ) . No such change was observed in T1 and T3. Table 2 Analysis of the Threshold Effect of Maternal Physical Activity During Pregnancy on Neonatal Birth Weight T1 T2 T3 Model I Linear effect, per SD increase 28.28 (−22.05, 78.61) 0.2716 19.76 (−22.51, 62.03) 0.3603 20.25 (−25.13, 65.62) 0.3825 Model II Inflection point 63.52 218.22 210.88 < Inflection point, per SD increase 394.01 (−130.18, 918.21) 0.1417 −12.92 (−60.25, 34.42) 0.5931 −5.16 (−60.84, 50.51) 0.8559 ≥ Inflection point, per SD increase 12.81 (−42.09, 67.70) 0.6478 544.04 (184.77, 903.32) 0.0032 239.26 (−43.69, 522.20) 0.0985 P for log likely ratio test 0.161 0.004 0.117 Sensitivity Analysis Sensitivity analysis was conducted to assess the robustness of the findings. We focused on analyzing normal pregnancies, excluding those with gestational diabetes, as shown in Table S2. After controlling for confounding factors, we found that physical activity during pregnancy in T1 (β: 72.34, 95% CI: 29.44 to 115.24, P = 0.0011) and T3 (β: 48.70, 95% CI: 1.65 to 95.76, P = 0.0434) remained positively associated with birth weight, while T2 showed no significant association (β: 11.34, 95% CI: -34.28 to 56.97, P = 0.6264). Discussion This study used a generalized linear model to analyze data from 337 pregnant women and found a U-shaped relationship between PA during late pregnancy (preterm) and BW. When energy expenditure exceeded 218.22 MET-h•wk^-1, each standard deviation increase in PA during pregnancy was associated with a 544.04g increase in neonatal BW. Current research on the relationship between PA during pregnancy and BW remains highly controversial. A cohort study conducted in Sweden, which included 1,153 pregnant women, showed no significant association between PA in early and mid-pregnancy and BW [ 18 ] . The study by Menke et al. also found that PA during pregnancy was not significantly associated with neonatal body composition at birth [ 19 ] .A study from Sri Lanka also yielded similar findings [ 20 ] . Several pooled randomized controlled trials have shown that moderate to vigorous physical activity during pregnancy can reduce the risk of macrosomia, but there is no significant association with birth weight [ 16 ] . In contrast, the results of this study indicate a U-shaped relationship between PA during pregnancy and BW. The inconsistent findings across different studies may be attributed to several factors. First, differences in the methods used to measure PA, including subjective questionnaires and objective monitoring devices, which vary in terms of accuracy. Second, there are variations in the timing, frequency, and intensity of PA measurements. Finally, differences in the study populations, such as ethnicity, socioeconomic status, prenatal monitoring conditions, diet, and other lifestyle factors, as well as varying levels of control over confounding factors, may also contribute to the heterogeneity of the study conclusions. Currently, most studies primarily focus on extreme BW outcomes such as macrosomia and low birth weight, while research exploring BW as a continuous variable is relatively limited. However, similar to the results of this study, the findings of Majewska et al. suggest that pregnant women with high exercise frequency may have an increased risk of macrosomia, indicating that PA during pregnancy could potentially increase BW [ 21 ] . A systematic review shows that PA during pregnancy has an inverted U-shaped relationship with BW, and moderate-intensity PA can result in an average increase of 61.5g in BW [ 22 ] . A secondary cohort study from the Gelis RCT, which included 1,994 pregnant women, found that pregnant women with higher levels of PA during late pregnancy had significantly higher BW compared to inactive women (P = 0.030) [ 23 ] . Similar to these results, our study, in the adjusted model, showed that when the energy expenditure of PA during late pregnancy (preterm) exceeded 218.22 MET-h•wk − 1 , each standard deviation increase was associated with a 544.04g increase in BW. Therefore, our study confirms the non-linear association between PA during late pregnancy (preterm) and BW. Although existing studies cannot fully explain the reasons, several factors may be involved. First, during late pregnancy, the maternal basal metabolic rate significantly increases, with the total daily energy expenditure being approximately 25% higher than in the non-pregnant state [ 24 ] . At this stage, if accompanied by high levels of PA, the mother faces greater energy supply and demand pressure, which is typically compensated by increased energy intake and improved nutrient absorption capacity, thus providing a richer nutritional foundation for the fetus [ 25 – 27 ] . Second, PA helps improve insulin resistance during pregnancy and reduce systemic inflammation levels, thereby enhancing the placenta's ability to utilize glucose [ 28 ] . The study by McDonald et al. found that fetuses of women with higher aerobic fitness during pregnancy had higher BW, which is speculated to be related to increased C-reactive protein and insulin signaling, thereby enhancing the fetus's efficiency in nutrient acquisition [ 29 ] . Third, PA can induce adaptive changes in placental structure and function, manifested as increased villous capillary density and upregulation of nutrient transporter proteins, thereby improving the efficiency of glucose, amino acid, and fatty acid transfer to the fetus [ 30 ] . The study by Adamo et al. pointed out that maternal exercise can enhance placental metabolic activity and gene expression through the signaling interaction between muscle-derived factors and placental-derived factors, thereby improving the nutrient supply capacity to the fetus [ 31 ] . To assess the robustness of the findings, we excluded pregnant women with gestational diabetes (GDM). After controlling for confounding factors, we found a positive correlation between PA during mid-pregnancy and late pregnancy (full-term) with BW, while T2 showed no significant association. It is important to note that a clear non-linear threshold exists in T2. Therefore, the "overall non-significant" result after including T2 in the linear model is understandable: the effect below the inflection point is minimal, which weakens the overall effect. Moreover, excluding GDM reduced the sample size, leading to a decrease in statistical power and further weakening the significance. Overall, the conclusion that the effect mainly occurs in mid-pregnancy and requires higher activity levels remains unchanged, indicating the robustness of the primary result. This study found a non-linear relationship between energy expenditure from PA during pregnancy and BW, particularly when PA energy expenditure exceeded 218.22 MET-h•wk^-1. Further increases in PA significantly contributed to higher BW. In clinical practice, pregnant women should be encouraged to maintain moderate PA, especially during late pregnancy, while avoiding prolonged sedentary behavior and excessive exercise. Both low and high levels of PA may have adverse effects on fetal growth. Therefore, developing personalized exercise guidance plans, with reasonable adjustments based on the woman's health status and PA levels, is crucial for optimizing prenatal health management and promoting healthy fetal development. Additionally, healthcare professionals should focus on balancing exercise levels to prevent the potential risks of excessive exercise to both the mother and fetus. This study has several strengths. First, through three follow-up visits, PA during pregnancy was dynamically monitored, allowing for a comprehensive evaluation of the long-term impact of PA on BW. Second, sensitivity analysis was performed to validate the robustness of the results, and non-linear algorithms were used to more precisely reveal the relationship between PA during pregnancy and BW. However, this study has some limitations. First, only singleton pregnancies were included, so the results may not be directly applicable to the multi-fetal pregnancy population. Second, as an observational study, it is inevitably subject to confounding factors, although we rigorously adjusted for confounders and assessed the robustness of the results through sensitivity analysis. We could only adjust for measurable confounders, but unmeasurable confounders could not be accounted for. Therefore, future high-quality clinical studies in larger populations are necessary to further validate our findings. The conclusion of this study is that PA during late pregnancy (preterm) exhibits a U-shaped relationship with BW, with a different association observed at an energy expenditure of 218.22 MET-h•wk^-1. When PA during pregnancy exceeds 218.22 MET-h•wk^-1, each standard deviation increase in PA is associated with a 544.04g increase in BW (β: 544.04, 95% CI: 184.77 to 903.32, P = 0.0032). The results emphasize the crucial role of moderate PA in promoting healthy fetal growth and suggest that pregnant women should aim to maintain weekly PA around 218.22 MET-h•wk^-1 to avoid excessive activity, which may increase the risk of macrosomia. Therefore, in prenatal health management, clinical healthcare providers should offer targeted guidance on adjusting PA based on the woman's individual circumstances to optimize maternal health management, prevent adverse pregnancy outcomes, and ensure maternal and fetal health. Declarations Acknowledgments We would like to express our sincere gratitude to Dr Xinglin Chen for their valuable guidance and assistance with study design and content. We would also like to acknowledge the financial support provided by Shenzhen Second People’s Hospital for this study. Their contributions were essential to the successful completion of this research project. Author contributions Shuqun Ren: Formal analysis, Methodology, Writing– original draft, Writing – review & editing. Xiaohong You: Writing– review& editing. Qian Zhao: Investigation, Writing– review & editing. Linlin Jiang: Resources, Validation, Writing– review & editing. Aihong Jin: Funding acquisition, Methodology, Resources, Writing – review & editing. Data availability statement The datasets generated during and/or analyzed during the current study are not publicly available, but are available from the corresponding author on reasonable request. Ethics statement This study has obtained approval from the Ethics Committee of the Second People’s Hospital of Shenzhen (Approval No: 202301502PJ) and the protocol was registered with ClinicalTrials.gov (registration number: ChiCTR2300078381). This study was conducted in accordance with the principles of the Declaration of Helsinki. The participants provided their written informed consent to participate in this study. Funding This study was supported by the Hospital-Level Clinical Research Project of Shenzhen Second People's Hospital (Project No.2023yjlcyj004) and the Sanming Project of Medicine in Shenzhen (No.SZSM202311013). Conflict of interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. References Faa G, Fanos V, Manchia M, et al. The fascinating theory of fetal programming of adult diseases: A review of the fundamentals of the Barker hypothesis[J]. J Public Health Res, 2024,13(1):1214327873. Stinson S E, Kromann Reim P, Lund M A V, et al. The interplay between birth weight and obesity in determining childhood and adolescent cardiometabolic risk[J]. EBioMedicine, 2024,105:105205. Jornayvaz F R, Vollenweider P, Bochud M, et al. Low birth weight leads to obesity, diabetes and increased leptin levels in adults: the CoLaus study[J]. Cardiovasc Diabetol, 2016,15:73. 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Physical Activity during Pregnancy and Newborn Body Composition: A Systematic Review[J]. Int J Environ Res Public Health, 2022,19(12). Pathirathna M L, Sekijima K, Sadakata M, et al. Effects of Physical Activity During Pregnancy on Neonatal Birth Weight[J]. Sci Rep, 2019,9(1):6000. Majewska P, Szablewska A. Associations Between Physical Activity in Pregnancy and Maternal, Perinatal, and Neonatal Parameters: A Single-Center Prospective Cohort Study[J]. J Clin Med, 2025,14(7). Bisson M, Lavoie-Guenette J, Tremblay A, et al. Physical Activity Volumes during Pregnancy: A Systematic Review and Meta-Analysis of Observational Studies Assessing the Association with Infant's Birth Weight[J]. AJP Rep, 2016,6(2):e170-e197. Hoffmann J, Gunther J, Geyer K, et al. Associations between Prenatal Physical Activity and Neonatal and Obstetric Outcomes-A Secondary Analysis of the Cluster-Randomized GeliS Trial[J]. J Clin Med, 2019,8(10). Butte N F, King J C. Energy requirements during pregnancy and lactation[J]. Public Health Nutr, 2005,8(7A):1010-1027. Most J, Dervis S, Haman F, et al. Energy Intake Requirements in Pregnancy[J]. Nutrients, 2019,11(8). Gilmore L A, Butte N F, Ravussin E, et al. Energy Intake and Energy Expenditure for Determining Excess Weight Gain in Pregnant Women[J]. Obstet Gynecol, 2016,127(5):884-892. Kopp-Hoolihan L E, van Loan M D, Wong W W, et al. Longitudinal assessment of energy balance in well-nourished, pregnant women[J]. Am J Clin Nutr, 1999,69(4):697-704. Piotrowska K, Zgutka K, Tkacz M, et al. Physical Activity as a Modern Intervention in the Fight against Obesity-Related Inflammation in Type 2 Diabetes Mellitus and Gestational Diabetes[J]. Antioxidants (Basel), 2023,12(8). McDonald S M, Mouro S, Wisseman B, et al. Influence of prenatal exercise on the relationship between maternal overweight and obesity and select delivery outcomes[J]. Sci Rep, 2022,12(1):17343. Pahlavani H A, Laher I, Weiss K, et al. Physical exercise for a healthy pregnancy: the role of placentokines and exerkines[J]. J Physiol Sci, 2023,73(1):30. Adamo K B, Goudreau A D, Corson A E, et al. Physically active pregnancies: Insights from the placenta[J]. Physiol Rep, 2024,12(11):e16104. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 02 Mar, 2026 Reviews received at journal 03 Oct, 2025 Reviewers agreed at journal 02 Oct, 2025 Reviewers invited by journal 01 Oct, 2025 Editor assigned by journal 23 Sep, 2025 Editor invited by journal 14 Aug, 2025 Submission checks completed at journal 13 Aug, 2025 First submitted to journal 13 Aug, 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. 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09:13:22","extension":"html","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":136251,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7350562/v1/32a50ad877cc208946076e7d.html"},{"id":93573870,"identity":"ccc97b3a-7230-46fa-aedd-b02baaef03eb","added_by":"auto","created_at":"2025-10-15 09:13:22","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":90812,"visible":true,"origin":"","legend":"\u003cp\u003eDescription of the study cohort\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7350562/v1/9c9e8112771ff0dde9798aed.jpg"},{"id":93573869,"identity":"3b17bb0a-d01d-45a7-aeec-eb18c85658fa","added_by":"auto","created_at":"2025-10-15 09:13:22","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":101199,"visible":true,"origin":"","legend":"\u003cp\u003eAssociation Between Physical Activity During Pregnancy and Neonatal Birth Weight. A threshold, nonlinear association between physical activity during pregnancy and neonatal birth weight was observed using a generalized additive model (GAM). The solid red line represents the smoothed curve fit between the variables, and the blue bands represent the 95% confidence interval of the fit.\u003c/p\u003e\n\u003cp\u003eAll models were adjusted for age, education level, occupation, average monthly family income, pre-pregnancy BMI, number of pregnancies, number of births, method of conception, and mode of delivery.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7350562/v1/03645a16c46c141244df6d79.jpg"},{"id":93576623,"identity":"82f1a56b-f316-4ad5-acbc-537bbf2eddba","added_by":"auto","created_at":"2025-10-15 09:37:22","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1002698,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7350562/v1/e4f3e6df-a6b3-41f6-ac2e-18a82c7937eb.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"The U-Shaped Relationship Between Pregnancy Physical Activity and Neonatal Birth Weight","fulltext":[{"header":"Introduction","content":"\u003cp\u003eNeonatal birth weight (BW) is an important indicator of fetal intrauterine development and is closely associated with metabolic health during childhood and even adulthood\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. Lower birth weight is associated with an increased risk of chronic diseases such as obesity, diabetes, and hypertension in adulthood\u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e. High birth weight, also known as macrosomia, is associated with an increased risk of metabolic syndrome, cardiovascular diseases, and other health issues in adulthood\u003csup\u003e[\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. Studies have shown that birth weight can influence insulin resistance, blood glucose, and lipid levels. For each 100-gram decrease in birth weight of full-term newborns, the incidence of insulin resistance and dyslipidemia in childhood significantly increases\u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e.However, birth weight not only impacts health through the weight itself but also exacerbates the risk of chronic diseases by influencing organ development and the early programming of metabolic systems\u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003ePhysical activity (PA) during pregnancy, as one of the most practical and scalable lifestyle interventions, has been shown to reduce the risk of pregnancy complications and adverse birth outcomes. Therefore, it is widely recommended as a proactive health behavior to improve pregnancy outcomes\u003csup\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e.The World Health Organization's 2020 Guidelines on Physical Activity and Sedentary Behaviour recommend that all pregnant women without medical contraindications engage in at least 150 to 300 minutes of moderate-intensity aerobic activity per week, combined with strength training, to achieve dual health benefits for both mother and baby\u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e.In the same year, the American College of Obstetricians and Gynecologists (ACOG) issued Committee Opinion No. 804, which stated that regular physical activity does not increase the risk of miscarriage, preterm birth, low birth weight, or macrosomia. It encourages healthy pregnant women to maintain or begin an exercise regimen following a safety assessment\u003csup\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eHowever, the impact of PA on BW remains a topic of significant debate. A 2023 systematic review and meta-analysis involving 16,524 pregnant women showed that prenatal exercise interventions did not significantly affect birth weight (BW), but they were associated with a 21% reduction in the risk of macrosomia\u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e. A study by Ma\u0026iacute;ra B. Malta et al. found that at least 150 minutes of leisure-time physical activity per week during late pregnancy was negatively associated with offspring birth weight\u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003ePotential reasons for the discrepancy in results include variations in the dosage of physical activity during pregnancy, differences in baseline BMI among pregnant women, and the presence of pregnancy-related complications. Moreover, existing studies primarily focus on populations from Europe and North America, while Asian pregnant women exhibit significant differences in physical activity patterns, dietary structure, and placental physiology, limiting the extrapolation of these findings. Therefore, this study focuses on Chinese pregnant women to observe the relationship between physical activity during pregnancy and neonatal birth weight, providing scientific evidence for the development of precise prenatal exercise prescriptions to improve maternal and neonatal outcomes.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStudy design and participants\u003c/h2\u003e\u003cp\u003eThis study is a prospective cohort study. We recruited primiparous pregnant women who underwent routine prenatal check-ups at the Obstetrics Outpatient Department and delivered at the Obstetrics Ward of Shenzhen Second People's Hospital between May 2023 and October 2023. The women were enrolled into the prospective cohort during their mid-pregnancy (T1, 14\u0026ndash;27 weeks) when they completed the first physical activity survey. The second survey was conducted during late pregnancy, preterm (T2, 28\u0026thinsp;+\u0026thinsp;6 to 32 weeks), and the third survey took place during late pregnancy, full-term (T3, 33 weeks to delivery), with continuous follow-up until delivery.\u003c/p\u003e\u003cp\u003eInclusion criteria: ① Age\u0026thinsp;\u0026ge;\u0026thinsp;20 years; ② Singleton pregnancy; ③ No mental or cognitive impairments, able to effectively communicate with the researchers or complete the questionnaire independently; ④ Voluntary participation and signing of informed consent; ⑤ Good physical health prior to pregnancy, with no history of diabetes, hypertension, heart disease, or other related conditions. Exclusion criteria: ① Pregnancy complications such as placenta previa or threatened miscarriage;② Severe complications such as peripartum cardiomyopathy, liver diseases, or hematologic disorders during pregnancy; ③ A history of psychological or psychiatric disorders. Exclusion criteria for data: ① Inaccurate questionnaire responses; ② Incomplete data that could impact the analysis of research outcomes. This study was approved by the Ethics Committee of Shenzhen Second People's Hospital (Ethics Approval No.: 2023-015-02PJ).\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eExposure\u003c/h3\u003e\n\u003cp\u003eThe exposure variable in this study is physical activity during late pregnancy, which was assessed using the Pregnancy Physical Activity Questionnaire (PPAQ). The results were recorded as continuous variables. The PPAQ was developed by American scholars, and the Chinese version of the PPAQ was adapted by Chinese researchers in 2012 to better suit the local context. The test-retest reliability of the Chinese version is 0.944, and its content validity is 0.940, demonstrating good reliability and validity. It is also significantly correlated with energy expenditure (r\u0026thinsp;=\u0026thinsp;0.768, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The questionnaire classifies physical activity by type and intensity, addressing the issue of low differentiation between different types of physical activity. It has been widely used for assessing physical activity levels during pregnancy.\u003c/p\u003e\u003cp\u003eThe Chinese version of the PPAQ includes four dimensions and 31 items: 13 items on household activities, 5 items on transportation, 8 items on recreational exercise, and 5 items on occupational activities. Physical activities are categorized based on intensity, with energy expenditure values referenced from the physical activity guidelines and expressed as metabolic equivalents (MET). Each item includes six options, each corresponding to a different weight coefficient. These are then multiplied by the corresponding energy expenditure values to calculate the weekly energy expenditure (MET-h\u0026bull;wk\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) for that activity.\u003c/p\u003e\u003cp\u003eAccording to the ACOG recommendations, physical activity with an energy expenditure of \u0026ge;\u0026thinsp;7.5 MET-h\u0026bull;wk\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e per week is classified as meeting the recommended level of physical activity during pregnancy, while\u0026thinsp;\u0026lt;\u0026thinsp;7.5 MET-h\u0026bull;wk\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e is considered insufficient.\u003c/p\u003e\n\u003ch3\u003eOutcomes\u003c/h3\u003e\n\u003cp\u003eThe primary outcome was BW (grams). BW was measured by the delivery room nurse as soon as possible after delivery (with the newborn undressed and unwrapped), using a calibrated electronic baby scale. The reading was accurate to 10 g and recorded in the delivery record. If multiple measurements were taken during the same delivery, the first valid measurement was used. To ensure data quality, we conducted consistency checks on the weight records: when significant discrepancies or missing data were found, medical records were reviewed and cross-checked with the delivery records. Inconsistent data were corrected or excluded.\u003c/p\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003eStatistical analysis\u003c/h2\u003e\u003cp\u003eContinuous variables are expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD) for normally distributed data or median (interquartile range, IQR) for skewed data, and categorical variables are presented as frequencies or percentages. For normally distributed continuous variables, one-way analysis of variance (ANOVA) was used; for skewed distributions, the Kruskal-Wallis H test was applied. Chi-square tests were used for group comparisons of categorical variables. Baseline characteristics were compared between the groups, with PA during pregnancy classified based on the ACOG recommendation. PA with energy expenditure\u0026thinsp;\u0026ge;\u0026thinsp;7.5 MET-h\u0026bull;wk\u003csup\u003e\u0026minus;\u003c/sup\u003e1 was classified as active, and \u0026lt;\u0026thinsp;7.5 MET-h\u0026bull;wk\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e as inactive\u003csup\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eUnivariate analysis was performed using linear regression to evaluate the relationship between PA during pregnancy and BW. Results are presented as regression coefficients with 95% confidence intervals (CIs). To standardize the comparison, PA during pregnancy data were first standardized by calculating Z-scores, and regression coefficients were estimated for each standard deviation increase in physical activity.\u003c/p\u003e\u003cp\u003eMultivariate analysis was performed using binary logistic regression, constructing three distinct models: the unadjusted model (without any covariate adjustment), the minimally adjusted model (adjusted for sociodemographic variables only), and the fully adjusted model (adjusted for all relevant covariates, as shown in Table\u0026nbsp;3). Covariates with variance inflation factors (VIFs) greater than 10 were removed from the fully adjusted model.\u003c/p\u003e\u003cp\u003eConsidering the potential non-linear relationship between PA during pregnancy and BW, smooth curve fitting (penalized spline method) was used to address non-linearity. A two-piecewise linear regression model was used to examine the saturation effect of PA during pregnancy on neonatal birth weight. The inflection point for PA was determined through exploratory analysis, where the trial inflection point was moved along a predefined interval to identify the point that maximized model likelihood. A log-likelihood ratio test was performed to compare the one-line linear regression model with the two-piecewise linear regression model.\u003c/p\u003e\u003cp\u003eTo assess the robustness of the findings, sensitivity analysis was conducted by excluding pregnant women with gestational diabetes. The analysis focused on the normal pregnancy group, evaluating the impact of PA on neonatal birth weight in the absence of gestational diabetes. This analysis verified the potential influence of gestational diabetes on the conclusions.\u003c/p\u003e\u003cp\u003eAll statistical analyses were performed using R software (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.R-project.org\u003c/span\u003e\u003cspan address=\"http://www.R-project.org\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e, The R Foundation) and EmpowerStats software (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.empowerstats.com\u003c/span\u003e\u003cspan address=\"http://www.empowerstats.com\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e, X\u0026amp;Y Solutions, Inc., Boston, MA, USA). A two-sided P-value of \u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eBaseline characteristics of nulliparous patients\u003c/h2\u003e\u003cp\u003eThis study included 360 pregnant women who attended regular prenatal check-ups at Shenzhen Second People's Hospital from May 2023 to October 2023. 5 cases were excluded due to absolute contraindications for physical activity (placenta previa), 5 cases were excluded due to pregnancy-induced hypertension, 3 cases were excluded due to pregnancy-associated arrhythmia, and 10 cases were excluded due to missing or erroneous physical activity data. A total of 337 pregnant women completed the survey. Details of the process can be found in the flowchart \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe participants were divided into two groups based on whether they met the recommended level of PA during pregnancy. The mean age of the 337 women was 31.26\u0026thinsp;\u0026plusmn;\u0026thinsp;4.07 years. The mean BW was 3195.80\u0026thinsp;\u0026plusmn;\u0026thinsp;403.60g. The characteristics of the mothers and newborns are shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\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\u003e Baseline Data of Pregnant Women by Physical Activity Level and Neonatal Birth Weight\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"10\"\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=\"char\" char=\".\" 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=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eT1\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eP Value\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003eT2\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eP Value\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e\u003cp\u003eT3\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eP Value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eInactive\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;194)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eActive\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;143)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eInactive\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;232)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eActive\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;105)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eInactive\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;215)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003eActive\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;122)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMaternal age, y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e31.06\u0026thinsp;\u0026plusmn;\u0026thinsp;4.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e31.54\u0026thinsp;\u0026plusmn;\u0026thinsp;3.89\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.334\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e31.13\u0026thinsp;\u0026plusmn;\u0026thinsp;4.13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e31.54\u0026thinsp;\u0026plusmn;\u0026thinsp;3.93\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.394\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e31.49\u0026thinsp;\u0026plusmn;\u0026thinsp;4.17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e30.86\u0026thinsp;\u0026plusmn;\u0026thinsp;3.87\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.173\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e21.46\u0026thinsp;\u0026plusmn;\u0026thinsp;3.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e21.59\u0026thinsp;\u0026plusmn;\u0026thinsp;3.03\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.714\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e21.60\u0026thinsp;\u0026plusmn;\u0026thinsp;3.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e21.33\u0026thinsp;\u0026plusmn;\u0026thinsp;2.97\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.464\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e21.40\u0026thinsp;\u0026plusmn;\u0026thinsp;3.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e21.72\u0026thinsp;\u0026plusmn;\u0026thinsp;2.96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.358\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGA weeks at delivery (wk)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e38.94\u0026thinsp;\u0026plusmn;\u0026thinsp;1.16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e39.09\u0026thinsp;\u0026plusmn;\u0026thinsp;1.04\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.222\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e38.96\u0026thinsp;\u0026plusmn;\u0026thinsp;1.16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e39.10\u0026thinsp;\u0026plusmn;\u0026thinsp;0.99\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.293\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e38.86\u0026thinsp;\u0026plusmn;\u0026thinsp;1.10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e39.26\u0026thinsp;\u0026plusmn;\u0026thinsp;1.07\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWeight gain, g\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e13.52\u0026thinsp;\u0026plusmn;\u0026thinsp;10.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e14.13\u0026thinsp;\u0026plusmn;\u0026thinsp;10.51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.599\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e13.29\u0026thinsp;\u0026plusmn;\u0026thinsp;9.19\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e14.87\u0026thinsp;\u0026plusmn;\u0026thinsp;13.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.202\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e13.33\u0026thinsp;\u0026plusmn;\u0026thinsp;9.99\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e14.57\u0026thinsp;\u0026plusmn;\u0026thinsp;11.43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.300\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBirthweight, g\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3163.38\u0026thinsp;\u0026plusmn;\u0026thinsp;409.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3240.11\u0026thinsp;\u0026plusmn;\u0026thinsp;393.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.085\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3172.51\u0026thinsp;\u0026plusmn;\u0026thinsp;398.17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3247.05\u0026thinsp;\u0026plusmn;\u0026thinsp;412.61\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.117\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e3172.31\u0026thinsp;\u0026plusmn;\u0026thinsp;380.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e3237.01\u0026thinsp;\u0026plusmn;\u0026thinsp;439.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.158\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBirth length, cm\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e49.33\u0026thinsp;\u0026plusmn;\u0026thinsp;1.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e49.09\u0026thinsp;\u0026plusmn;\u0026thinsp;4.49\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.485\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e49.06\u0026thinsp;\u0026plusmn;\u0026thinsp;3.67\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e49.61\u0026thinsp;\u0026plusmn;\u0026thinsp;1.76\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.140\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e49.04\u0026thinsp;\u0026plusmn;\u0026thinsp;3.76\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e49.57\u0026thinsp;\u0026plusmn;\u0026thinsp;1.82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.147\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ehead circumference, cm\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e33.26\u0026thinsp;\u0026plusmn;\u0026thinsp;1.24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e33.48\u0026thinsp;\u0026plusmn;\u0026thinsp;1.21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.099\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e33.36\u0026thinsp;\u0026plusmn;\u0026thinsp;1.27\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e33.33\u0026thinsp;\u0026plusmn;\u0026thinsp;1.16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.847\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e33.43\u0026thinsp;\u0026plusmn;\u0026thinsp;1.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e33.22\u0026thinsp;\u0026plusmn;\u0026thinsp;1.24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.141\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eEducational Level\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.013\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.021\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.678\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHigh School and Below\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e32 (16.49%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12 (8.45%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e37 (16.02%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7 (6.67%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e30 (14.02%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e14 (11.48%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAssociate's or Bachelor's Degree\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e150 (77.32%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e111 (78.17%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e177(76.62%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e84 (80.00%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e163 (76.17%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e98 (80.33%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGraduate Degree and Above\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e12 (6.19%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e19 (13.38%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e17 (7.36%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e14 (13.33%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e21 (9.81%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e10 (8.20%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eProfession\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.487\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.736\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.493\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eUnemployed\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e38 (19.59%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e35 (24.65%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e53 (22.94%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e20 (19.05%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e50 (23.37%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e23 (18.85%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCorporate Employee\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e126 (64.95%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e89 (62.68%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e144(62.34%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e71 (67.62%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e131 (61.21%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e84 (68.85%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGovernment Employee\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30 (15.46%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e18 (12.68%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e34 (14.72%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e14 (13.33%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e33 (15.42%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e15 (12.30%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003eAverage Monthly Household Income Per Capita ( Yuan)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.038\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.126\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.173\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;10000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e67 (34.54%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e31 (21.83%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e75 (32.47%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e23 (21.90%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e69 (32.24%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e29 (23.77%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e10000\u0026thinsp;~\u0026thinsp;20000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e76 (39.18%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e64 (45.07%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e90 (38.96%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e50 (47.62%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e82 (38.32%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e58 (47.54%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;20000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e51 (26.29%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e47 (33.10%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e66 (28.57%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e32 (30.48%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e63 (29.44%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e35 (28.69%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePregnancy Intention\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.929\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.962\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.646\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePlanned\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e133 (68.56%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e98 (69.01%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e159 (68.83%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e72 (68.57%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e149 (69.63%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e82 (67.21%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eUnplanned\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e61 (31.44%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e44 (30.99%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e72 (31.17%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e33 (31.43%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e65 (30.37%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e40 (32.79%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNumber of pregnancy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.260\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.422\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.139\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e84 (43.30%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e71 (50.00%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e101 (43.72%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e54 (51.43%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e90 (42.06%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e65 (53.28%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e48 (24.74%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e37 (26.06%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e61 (26.41%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e24 (22.86%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e58 (27.10%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e27 (22.13%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e62 (31.96%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e34 (23.94%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e69 (29.87%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e27 (25.71%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e66 (30.84%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e30 (24.59%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNumber of Births\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.058\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.078\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.225\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e119 (61.34%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e98 (69.01%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e142 (61.47%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e75 (71.43%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e131 (61.21%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e86 (70.49%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e60 (30.93%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e41 (28.87%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e73 (31.60%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e28 (26.67%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e70 (32.71%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e31 (25.41%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e15 (7.73%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (2.11%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e16 (6.93%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2 (1.90%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e13 (6.07%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e5 (4.10%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDelivery way\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.841\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.090\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVaginal delivery\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e125 (64.43%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e93 (65.49%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e143 (61.90%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e75 (71.43%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e124 (57.94%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e94 (77.05%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCesarean delivery\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e69 (35.57%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e49 (34.51%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e88 (38.10%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e30 (28.57%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e90 (42.06%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e28 (22.95%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNewborn Gender\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.439\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.565\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.695\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMale\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e108 (55.67%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e73 (51.41%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e122 (52.81%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e59 (56.19%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e117 (54.67%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e64 (52.46%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFemale\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e86 (44.33%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e69 (48.59%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e109 (47.19%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e46 (43.81%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e97 (45.33%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e58 (47.54%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAnemia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.709\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.326\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.572\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e80 (41.24%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e58 (40.85%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e92 (39.83%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e46 (43.81%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e87 (40.65%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e51 (41.80%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e60 (30.93%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e43 (30.28%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e70 (30.30%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e33 (31.43%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e65 (30.37%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e38 (31.15%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e54 (27.84%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e41 (28.87%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e69 (29.87%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e25 (24.76%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e62 (28.97%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e33 (27.05%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eUnivariate Analysis of the BW\u003c/h3\u003e\n\u003cp\u003eUnivariate analysis \u003cb\u003e(Table S1)\u003c/b\u003e showed that pre-pregnancy BMI, gestational weight gain, education level, occupation, anemia, number of deliveries, gestational age at delivery, neonatal sex, and neonatal head circumference and length were associated with neonatal birth weight (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\n\u003ch3\u003eResults of nonlinear association between PA during pregnancy and BW\u003c/h3\u003e\n\u003cp\u003eNon-linear associations between physical activity during pregnancy (PA) and the duration of the first stage of labor were observed through smooth curve fitting and generalized additive models. Our results indicate that after adjusting for age, education level, occupation, household per capita monthly income, number of deliveries, pre-pregnancy BMI, gestational weight gain, and gestational age at delivery, the relationship between PA during pregnancy in T2 and BW exhibited a threshold effect. The inflection point was identified at 218.22 MET-h\u0026bull;wk^-1. When PA during pregnancy exceeded 218.22 MET-h\u0026bull;wk^-1, each standard deviation increase in PA was associated with an increase in BW of 544.04g (β: 544.04, 95% CI: 184.77 to 903.32, P\u0026thinsp;=\u0026thinsp;0.0032). However, when PA during pregnancy was below 218.22 MET-h\u0026bull;wk^-1, BW did not change with increasing PA (β: -12.92, 95% CI: -60.25 to 34.42, P\u0026thinsp;=\u0026thinsp;0.5931) \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e \u003cb\u003eand\u003c/b\u003e Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. No such change was observed in T1 and T3.\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 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e Analysis of the Threshold Effect of Maternal Physical Activity During Pregnancy on Neonatal Birth Weight\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\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eT1\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eT2\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eT3\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eModel I\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLinear effect,\u003c/p\u003e\u003cp\u003eper SD increase\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e28.28 (\u0026minus;22.05, 78.61) 0.2716\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e19.76 (\u0026minus;22.51, 62.03) 0.3603\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e20.25 (\u0026minus;25.13, 65.62) 0.3825\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eModel II\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eInflection point\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e63.52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e218.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e210.88\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; Inflection point,\u003c/p\u003e\u003cp\u003eper SD increase\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e394.01 (\u0026minus;130.18, 918.21) 0.1417\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026minus;12.92 (\u0026minus;60.25, 34.42) 0.5931\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026minus;5.16 (\u0026minus;60.84, 50.51) 0.8559\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; Inflection point,\u003c/p\u003e\u003cp\u003eper SD increase\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12.81 (\u0026minus;42.09, 67.70) 0.6478\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e544.04 (184.77, 903.32) 0.0032\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e239.26 (\u0026minus;43.69, 522.20) 0.0985\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eP for log likely ratio test\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.161\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.004\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.117\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003eSensitivity Analysis\u003c/h2\u003e\u003cp\u003eSensitivity analysis was conducted to assess the robustness of the findings. We focused on analyzing normal pregnancies, excluding those with gestational diabetes, as shown in Table S2. After controlling for confounding factors, we found that physical activity during pregnancy in T1 (β: 72.34, 95% CI: 29.44 to 115.24, P\u0026thinsp;=\u0026thinsp;0.0011) and T3 (β: 48.70, 95% CI: 1.65 to 95.76, P\u0026thinsp;=\u0026thinsp;0.0434) remained positively associated with birth weight, while T2 showed no significant association (β: 11.34, 95% CI: -34.28 to 56.97, P\u0026thinsp;=\u0026thinsp;0.6264).\u003c/p\u003e\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study used a generalized linear model to analyze data from 337 pregnant women and found a U-shaped relationship between PA during late pregnancy (preterm) and BW. When energy expenditure exceeded 218.22 MET-h\u0026bull;wk^-1, each standard deviation increase in PA during pregnancy was associated with a 544.04g increase in neonatal BW.\u003c/p\u003e\u003cp\u003eCurrent research on the relationship between PA during pregnancy and BW remains highly controversial. A cohort study conducted in Sweden, which included 1,153 pregnant women, showed no significant association between PA in early and mid-pregnancy and BW\u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e. The study by Menke et al. also found that PA during pregnancy was not significantly associated with neonatal body composition at birth\u003csup\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e.A study from Sri Lanka also yielded similar findings\u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e. Several pooled randomized controlled trials have shown that moderate to vigorous physical activity during pregnancy can reduce the risk of macrosomia, but there is no significant association with birth weight\u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e. In contrast, the results of this study indicate a U-shaped relationship between PA during pregnancy and BW. The inconsistent findings across different studies may be attributed to several factors. First, differences in the methods used to measure PA, including subjective questionnaires and objective monitoring devices, which vary in terms of accuracy. Second, there are variations in the timing, frequency, and intensity of PA measurements. Finally, differences in the study populations, such as ethnicity, socioeconomic status, prenatal monitoring conditions, diet, and other lifestyle factors, as well as varying levels of control over confounding factors, may also contribute to the heterogeneity of the study conclusions.\u003c/p\u003e\u003cp\u003eCurrently, most studies primarily focus on extreme BW outcomes such as macrosomia and low birth weight, while research exploring BW as a continuous variable is relatively limited. However, similar to the results of this study, the findings of Majewska et al. suggest that pregnant women with high exercise frequency may have an increased risk of macrosomia, indicating that PA during pregnancy could potentially increase BW\u003csup\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e. A systematic review shows that PA during pregnancy has an inverted U-shaped relationship with BW, and moderate-intensity PA can result in an average increase of 61.5g in BW\u003csup\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/sup\u003e. A secondary cohort study from the Gelis RCT, which included 1,994 pregnant women, found that pregnant women with higher levels of PA during late pregnancy had significantly higher BW compared to inactive women (P\u0026thinsp;=\u0026thinsp;0.030)\u003csup\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/sup\u003e. Similar to these results, our study, in the adjusted model, showed that when the energy expenditure of PA during late pregnancy (preterm) exceeded 218.22 MET-h\u0026bull;wk\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, each standard deviation increase was associated with a 544.04g increase in BW. Therefore, our study confirms the non-linear association between PA during late pregnancy (preterm) and BW.\u003c/p\u003e\u003cp\u003eAlthough existing studies cannot fully explain the reasons, several factors may be involved. First, during late pregnancy, the maternal basal metabolic rate significantly increases, with the total daily energy expenditure being approximately 25% higher than in the non-pregnant state\u003csup\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/sup\u003e. At this stage, if accompanied by high levels of PA, the mother faces greater energy supply and demand pressure, which is typically compensated by increased energy intake and improved nutrient absorption capacity, thus providing a richer nutritional foundation for the fetus\u003csup\u003e[\u003cspan additionalcitationids=\"CR26\" citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/sup\u003e. Second, PA helps improve insulin resistance during pregnancy and reduce systemic inflammation levels, thereby enhancing the placenta's ability to utilize glucose\u003csup\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/sup\u003e. The study by McDonald et al. found that fetuses of women with higher aerobic fitness during pregnancy had higher BW, which is speculated to be related to increased C-reactive protein and insulin signaling, thereby enhancing the fetus's efficiency in nutrient acquisition\u003csup\u003e[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e. Third, PA can induce adaptive changes in placental structure and function, manifested as increased villous capillary density and upregulation of nutrient transporter proteins, thereby improving the efficiency of glucose, amino acid, and fatty acid transfer to the fetus\u003csup\u003e[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/sup\u003e. The study by Adamo et al. pointed out that maternal exercise can enhance placental metabolic activity and gene expression through the signaling interaction between muscle-derived factors and placental-derived factors, thereby improving the nutrient supply capacity to the fetus\u003csup\u003e[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eTo assess the robustness of the findings, we excluded pregnant women with gestational diabetes (GDM). After controlling for confounding factors, we found a positive correlation between PA during mid-pregnancy and late pregnancy (full-term) with BW, while T2 showed no significant association. It is important to note that a clear non-linear threshold exists in T2. Therefore, the \"overall non-significant\" result after including T2 in the linear model is understandable: the effect below the inflection point is minimal, which weakens the overall effect. Moreover, excluding GDM reduced the sample size, leading to a decrease in statistical power and further weakening the significance. Overall, the conclusion that the effect mainly occurs in mid-pregnancy and requires higher activity levels remains unchanged, indicating the robustness of the primary result.\u003c/p\u003e\u003cp\u003eThis study found a non-linear relationship between energy expenditure from PA during pregnancy and BW, particularly when PA energy expenditure exceeded 218.22 MET-h\u0026bull;wk^-1. Further increases in PA significantly contributed to higher BW. In clinical practice, pregnant women should be encouraged to maintain moderate PA, especially during late pregnancy, while avoiding prolonged sedentary behavior and excessive exercise. Both low and high levels of PA may have adverse effects on fetal growth. Therefore, developing personalized exercise guidance plans, with reasonable adjustments based on the woman's health status and PA levels, is crucial for optimizing prenatal health management and promoting healthy fetal development. Additionally, healthcare professionals should focus on balancing exercise levels to prevent the potential risks of excessive exercise to both the mother and fetus.\u003c/p\u003e\u003cp\u003eThis study has several strengths. First, through three follow-up visits, PA during pregnancy was dynamically monitored, allowing for a comprehensive evaluation of the long-term impact of PA on BW. Second, sensitivity analysis was performed to validate the robustness of the results, and non-linear algorithms were used to more precisely reveal the relationship between PA during pregnancy and BW. However, this study has some limitations. First, only singleton pregnancies were included, so the results may not be directly applicable to the multi-fetal pregnancy population. Second, as an observational study, it is inevitably subject to confounding factors, although we rigorously adjusted for confounders and assessed the robustness of the results through sensitivity analysis. We could only adjust for measurable confounders, but unmeasurable confounders could not be accounted for. Therefore, future high-quality clinical studies in larger populations are necessary to further validate our findings.\u003c/p\u003e\u003cp\u003eThe conclusion of this study is that PA during late pregnancy (preterm) exhibits a U-shaped relationship with BW, with a different association observed at an energy expenditure of 218.22 MET-h\u0026bull;wk^-1. When PA during pregnancy exceeds 218.22 MET-h\u0026bull;wk^-1, each standard deviation increase in PA is associated with a 544.04g increase in BW (β: 544.04, 95% CI: 184.77 to 903.32, P\u0026thinsp;=\u0026thinsp;0.0032). The results emphasize the crucial role of moderate PA in promoting healthy fetal growth and suggest that pregnant women should aim to maintain weekly PA around 218.22 MET-h\u0026bull;wk^-1 to avoid excessive activity, which may increase the risk of macrosomia. Therefore, in prenatal health management, clinical healthcare providers should offer targeted guidance on adjusting PA based on the woman's individual circumstances to optimize maternal health management, prevent adverse pregnancy outcomes, and ensure maternal and fetal health.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to express our sincere gratitude to Dr Xinglin Chen for their valuable guidance and assistance with study design and content. We would also like to acknowledge the financial support provided by Shenzhen Second People\u0026rsquo;s Hospital for this study. Their contributions were essential to the successful completion of this research project.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eShuqun Ren: Formal analysis, Methodology, Writing\u0026ndash; original draft, Writing \u0026ndash; review \u0026amp; editing. Xiaohong You: Writing\u0026ndash; review\u0026amp; editing. Qian Zhao: Investigation, Writing\u0026ndash; review \u0026amp; editing. Linlin Jiang: Resources, Validation, Writing\u0026ndash; review \u0026amp; editing. Aihong Jin: Funding acquisition, Methodology, Resources, Writing \u0026ndash; review \u0026amp; editing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated during and/or analyzed during the current study are not publicly available, but are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study has obtained approval from the Ethics Committee of the Second People\u0026rsquo;s Hospital of Shenzhen (Approval No: 202301502PJ) and the protocol was registered with ClinicalTrials.gov (registration number: ChiCTR2300078381). This study was conducted in accordance with the principles of the Declaration of Helsinki. The participants provided their written informed consent to participate in this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was supported by the Hospital-Level Clinical Research Project of Shenzhen Second People\u0026apos;s Hospital (Project No.2023yjlcyj004) and the Sanming Project of Medicine in Shenzhen (No.SZSM202311013).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that the research was conducted in the absence of any commercial or financial relationships that could be\u0026nbsp;construed as a potential conflict of interest.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eFaa G, Fanos V, Manchia M, et al. The fascinating theory of fetal programming of adult diseases: A review of the fundamentals of the Barker hypothesis[J]. 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Associations between Prenatal Physical Activity and Neonatal and Obstetric Outcomes-A Secondary Analysis of the Cluster-Randomized GeliS Trial[J]. J Clin Med, 2019,8(10).\u003c/li\u003e\n\u003cli\u003eButte N F, King J C. Energy requirements during pregnancy and lactation[J]. Public Health Nutr, 2005,8(7A):1010-1027.\u003c/li\u003e\n\u003cli\u003eMost J, Dervis S, Haman F, et al. Energy Intake Requirements in Pregnancy[J]. Nutrients, 2019,11(8).\u003c/li\u003e\n\u003cli\u003eGilmore L A, Butte N F, Ravussin E, et al. Energy Intake and Energy Expenditure for Determining Excess Weight Gain in Pregnant Women[J]. Obstet Gynecol, 2016,127(5):884-892.\u003c/li\u003e\n\u003cli\u003eKopp-Hoolihan L E, van Loan M D, Wong W W, et al. Longitudinal assessment of energy balance in well-nourished, pregnant women[J]. Am J Clin Nutr, 1999,69(4):697-704.\u003c/li\u003e\n\u003cli\u003ePiotrowska K, Zgutka K, Tkacz M, et al. Physical Activity as a Modern Intervention in the Fight against Obesity-Related Inflammation in Type 2 Diabetes Mellitus and Gestational Diabetes[J]. Antioxidants (Basel), 2023,12(8).\u003c/li\u003e\n\u003cli\u003eMcDonald S M, Mouro S, Wisseman B, et al. Influence of prenatal exercise on the relationship between maternal overweight and obesity and select delivery outcomes[J]. Sci Rep, 2022,12(1):17343.\u003c/li\u003e\n\u003cli\u003ePahlavani H A, Laher I, Weiss K, et al. Physical exercise for a healthy pregnancy: the role of placentokines and exerkines[J]. J Physiol Sci, 2023,73(1):30.\u003c/li\u003e\n\u003cli\u003eAdamo K B, Goudreau A D, Corson A E, et al. Physically active pregnancies: Insights from the placenta[J]. Physiol Rep, 2024,12(11):e16104.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Physical activity, Pregnancy, Birthweight, U-shaped relationship","lastPublishedDoi":"10.21203/rs.3.rs-7350562/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7350562/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study prospectively analyzed the relationship between physical activity during pregnancy and neonatal birth weight in 337 singleton pregnant women in Shenzhen, China. The participants were enrolled from May to October 2023 at the Shenzhen Second People's Hospital, where they underwent routine prenatal check-ups and deliveries. The physical activity during pregnancy was assessed three times using the Pregnancy Physical Activity Questionnaire (PPAQ) at three different stages: mid-pregnancy (T1), late pregnancy (T2, preterm), and late pregnancy (T3, full-term).After adjusting for confounding factors using generalized additive models (GAM) and smooth curve fitting, a U-shaped relationship was observed between physical activity during pregnancy and neonatal birth weight. When physical activity exceeded 218.22 MET-h\u0026bull;wk\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, each standard deviation increase in physical activity was associated with a 544.04g increase in birth weight (β: 544.04, 95% CI: 184.77 to 903.32, P\u0026thinsp;=\u0026thinsp;0.0032). No significant association was found below this threshold. The results suggest that moderate to higher levels of physical activity during late pregnancy are beneficial for fetal weight gain, whereas both low and excessively high levels may be detrimental. Clinically, individualized and balanced physical activity prescriptions during pregnancy should be developed.\u003c/p\u003e","manuscriptTitle":"The U-Shaped Relationship Between Pregnancy Physical Activity and Neonatal Birth Weight","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-15 09:13:17","doi":"10.21203/rs.3.rs-7350562/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-03-02T06:27:20+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-03T17:42:31+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"137053980334301678736778442595667881012","date":"2025-10-02T13:45:59+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-10-01T18:03:11+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-23T13:08:54+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-08-14T12:27:49+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-13T13:16:18+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-08-13T13:12:55+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"bc21deaf-370c-4220-854b-35c1b1bdfacd","owner":[],"postedDate":"October 15th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":56141809,"name":"Health sciences/Diseases"},{"id":56141810,"name":"Health sciences/Health care"},{"id":56141811,"name":"Health sciences/Medical research"},{"id":56141812,"name":"Health sciences/Risk factors"}],"tags":[],"updatedAt":"2026-04-21T08:09:27+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-15 09:13:17","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7350562","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7350562","identity":"rs-7350562","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}