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Background The most serious problem during vaginal birth after caesarean section (VBAC) is the risk of uterine rupture but there is controversy regarding important related factors. With the relaxation of birth policy in China, the maternal and perinatal outcomes after uterine rupture during VBAC are a societal concern. The lack of any large-scale study of uterine rupture during VBAC in China underscores the need for more research evidence. Methods We studied singleton pregnant women with VBAC from 2012 to 2019 registered in China’s National Maternal Near-Miss Surveillance System (NMNMSS). First, we calculated the incidence of uterine rupture during VBAC. Second, using a logistic regression model with weighting for the sampling distribution of the population and clustering of births within hospitals, we examined the association of sociodemographic and obstetric characteristics and maternal diseases with uterine rupture during VBAC. With multivariable logistic regression, adjusted odds ratio were estimated using two models. Finally, we compared the risk of adverse maternal and perinatal outcomes in women with and without uterine rupture during VBAC. Results This study included 155774 singleton pregnant women with VBAC, and the incidence of uterine rupture was 0.23%. Characteristics associated with the increased risk of uterine rupture during VBAC included two (aOR = 1.70; 95% CI: 1.06–2.73) and three or more (aOR = 2.59; 95% CI: 0.54–12.44) previous caesarean sections, delivery at 42 weeks or later (aOR = 2.62; 95% CI: 1.58–4.35), and foetal birthweight greater than 4000 g (aOR = 1.93; 95% CI: 1.30–2.87). Compared with those without these conditions, the risk of uterine rupture during VBAC among women with amniotic fluid embolism, severe anaemia, placenta accreta spectrum, placental abruption, preeclampsia or eclampsia, and mild anaemia was 25.7-fold, 15.89-fold, 4.17-fold, 3.96-fold, and 2.49-fold higher, respectively. The incidence of adverse maternal outcomes during VBAC was higher in women with uterine rupture than in women without. Conclusion The incidence of uterine rupture during VBAC is comparable between China and some developed countries. In the clinical medical practice of obstetrics, it is necessary to be vigilant to factors associated with uterine rupture during VBAC and identify uterine rupture as soon as possible to improve maternal and perinatal outcomes.

Objective: To assess the impact of applying published fetal growth references or standards in the Chinese mainland population and to compare their ability to predict newborns small- for- gestational- age (SGA). Design: Retrospective observational study. Setting: A tertiary hospital in Shenzhen, a Chinese city with the most immigrants. Population: All pregnant women (n=106,455) who booked for prenatal care with ultrasound measurements for fetal biometry between 2012 and 2019. Methods: A fractional polynomial regression model was applied to construct Shenzhen fetal growth chart ranges for HC, BPD, AC, and FL. The differences between Shenzhen charts and published charts were quantified by calculating the Z-score. Main outcome measures: The impact of applying these published charts was quantified by calculating the proportions of fetuses with biometric measurements below the 3rd centile of these charts. The sensitivity and area under the receiver operating curves of published charts to predict neonatal SGA (birthweight

Background As reported, 27-93 % of pregnant women take at least one drug during pregnancy. However, drug exposure during pregnancy still lacks sufficient foetal safety evidence of human origin. It is urgent to fill the knowledge gap about medication safety during pregnancy for optimization of maternal disease treatment and pregnancy drug consultation. Methods and analysis The China Teratology Birth Cohort (CTBC) was established in 2019 and is a hospital-based open-ended prospective cohort study with the aim of assessing drug safety during pregnancy. Pregnant women who set up the pregnancy health records in the first trimester or who seek drug consultation regardless of gestational age in the member hospitals are recruited. Enrolled pregnant women need to be investigated four times, namely, 6–14 and 24–28 weeks of gestational age, before discharge after hospital delivery, and 28–42 days after birth. Maternal medication exposure during pregnancy is the focus of the CTBC. For drugs, information on the type, name, and route of medication; start and end time of medication; single dose; frequency of medication; dosage form; manufacturer; and reason for medication is collected. The adverse pregnancy outcomes collected in the study include birth defects, stillbirth, spontaneous abortion, preterm birth, post-term birth, low birth weight, macrosomia, small for gestational age, large for gestational age and low Apgar score. CTBC uses an electronic questionnaire for data collection and a cloud system for data management. Biological samples are collected if informed consents are obtained. Multi-level logistic regression, mixed-effect negative binomial distribution regression and spline function regression are used to explore the effect of drugs on the occurrence of birth defects. Discussion The findings of the study will assist in further understanding the risk of birth defects and other adverse pregnancy outcomes associated with maternal drug exposure and developing the optimal treatment plans and drug counselling for pregnant women. Trial registration This study was approved by the Research Ethics Committee of the West China Second Hospital of Sichuan University and registered at the Chinese Clinical Trial Registry (http://www.chictr.org.cn/index.aspx, registration number ChiCTR1900022569).

Additional file 3. The relative risks in different parity and previous caesatean section of women by age, China.

Background Currently, there are no studies on changes in the incidence of uterine rupture or maternal and foetal outcomes in women with uterine rupture during different birth policy periods in China. Moreover, the results of association studies of maternal age, parity and previous caesarean section number with the risk of maternal and foetal outcomes in women with uterine rupture have not been consistent. This research aims to conduct and discuss the above two aspects. Methods We included singleton pregnant women with no maternal complications other than uterine rupture from January 2012 to June 2019 in China’s National Maternal Near Miss Surveillance System. The data in this study did not differentiate between complete and partial uterine rupture and uterine dehiscence. Through Poisson regression analysis with a robust variance estimator, we compared the incidences of uterine rupture and maternal and foetal outcomes in women with uterine rupture during different birth policy periods in China and determined the relationship between maternal age, parity or previous caesarean section number and uterine rupture or maternal and foetal outcomes in women with uterine rupture. Results This study included 8,637,723 pregnant women. The total incidences of uterine rupture were 0.13% (12,934) overall, 0.05% during the one-child policy, 0.12% during the partial two-child policy (aRR = 1.96; 95% CI: 1.53–2.52) and 0.22% (aRR = 2.89; 95% CI: 1.94 4.29) during the universal two-child policy. The maternal near miss and stillbirth rates in women with uterine rupture were respectively 2.35% (aRR = 17.90; 95% CI: 11.81–27.13) and 2.12% (aRR = 4.10; 95% CI: 3.19 5.26) overall, 5.46 and 8.18% during the first policy, 1.72% (aRR = 0.60; 95% CI: 0.32–1.17) and 2.02% (aRR = 0.57; 95% CI: 0.37–0.83) during the second policy, and 1.99% (aRR = 0.90; 95% CI: 0.52–1.53) and 1.04% (aRR = 0.36; 95% CI: 0.24–0.54) during the third policy. The risk of uterine rupture increased with parity and previous caesarean section number. Conclusion The uterine rupture rate in China continues to increase among different birth policy periods, and the risk of maternal near miss among women with uterine rupture has not significantly improved. The Chinese government, obstetricians, and scholars should work together to reverse the rising rate of uterine rupture and improve the pregnancy outcomes in women with uterine rupture.