The trend of caesarean birth rate changes in China after 'universal two-child policy' era: a population-based study in 2013-2018.

The universal two-child policy in China which was announced in October 2015 might affect the caesarean birth rate. Few studies reported the caesarean birth rate affected by the policy especially after the universal two-child policy period. This study aimed to demonstrate the caesarean birth rate changes before and after the universal two-child policy and further elaborate the underlying influencing factors. This nationwide, retrospective, population-based study was based on National Free Pre-Pregnancy Check-ups Project (NFPCP). Couples planning to conceive in next 6 months were encouraged to participate in NFPCP. Baseline information was collected using a standardized questionnaire with a face-to-face interview, and medical examinations were conducted. Two rounds of follow-up interviews were then conducted by trained nurses to update pregnancy status and outcomes. NFPCP participants who completed deliveries before December 31, 2018, were included in the current study. We used marginal effect of year to examine the trend of caesarean birth rate over time and interrupted time series (ITS) analysis to determine impacts of the universal two-child policy on the trend of caesarean birth rate. A total of 9,398,045 participants were included in the final analysis. High-risk factors to increase caesarean birth rate were identified. In the current study, the standardized caesarean birth rate declined from 34.1% in 2013 to 31.8% in 2015 and increased to 35.6% in 2018. ITS analysis showed the caesarean birth rate decreased by 0.1% (95% CI 0.1–0.1) per month before the release of universal two-child policy, 1.3% (95% CI 0.6–2.1%) absolute drop during the policy release month, and increased by 0.2% (95% CI 0.1–0.2%) per month after the policy implementation. For the period after the policy release, the increasing trends were observed in rural participants and urban primiparas. The prevalence of caesarean birth rates within China varied regionally. The decreasing trend of caesarean birth rate was reported after immediate release of the universal two-child policy. An increasing trend of caesarean birth rate was observed 2–3 years after the policy. It reminds us that the caesarean birth rate control is a long-lasting process and all the strategies need to be continually reinforced.