Previous mode of delivery affects subsequent pregnancy outcomes: a Chinese birth register study.

Background: With the comprehensive implementation of the second child policy in China, the proportion of multiparous women has increased dramatically in the past few years. As nearly half of them have a history of previous cesarean delivery, there is widespread concern regarding complications of their pregnancy.

Methods: The aim of this study was to evaluate the effect of the previous delivery mode on subsequent pregnancy outcomes in the real world based on data from a Chinese birth registry. Birth registry data from July 1, 2016 to June 30, 2017 among a Chinese population were collected and analyzed retrospectively. This study included 14 representative hospitals from 10 provinces of China. All delivery data were collected by an internet-based system using a birth registration platform. The study enrolled 36,355 multiparas. Information extracted for analysis included basic demographic characteristics, previous delivery mode, current delivery mode, major maternal complications, and neonatal outcomes. Pregnancy outcomes of women with previous cesarean delivery (PCS group, n=14,774) were compared with the outcomes of women with previous vaginal delivery (PVD group, n=21,581).

Results: There were statistically significant differences in the major pregnancy outcomes between the PCS group and the PVD group. The PCS group had a higher incidence of cesarean section (CS), placenta previa, postpartum hemorrhage, uterus rupture, hysterectomy, gestational diabetes, gestational hypertension, delivery before 37 weeks of gestation, low birth weight, and Apgar Score at 5 min ≤3.

Conclusions: Women with previous cesarean delivery had poorer pregnancy outcomes than women with previous vaginal delivery. Avoiding unnecessary CS, especially in primiparas is essential to improving maternal and neonatal outcomes in later pregnancies.