The possible impact of the universal two-child policy on pregnancy outcomes

Purpose The implementation of the universal two-child policy contributes to adverse pregnancy outcomes, but how the policy change leads to adverse pregnancy outcomes is not well elaborated. In this study, we aimed to compare maternal characteristics and complications, accessed the change in the proportion of maternal characteristics and maternal complications, and evaluated the mediation of maternal characteristics on maternal complications. Methods Demographic and clinical data of three-level sample facilities were extracted from China’s National Maternity Near Miss Obstetrics Surveillance System from Jan 1, 2012 to May 31, 2021. The associations between the universal two-child policy and maternal risk factors, the universal two-child policy and maternal complications, and maternal risk factors and maternal complications were evaluated using multivariate logistic regression analyses, with odds ratios (ORs) and 95% confidence intervals (CIs). Mediation analysis was used to estimate the potential mediation effects on the associations between the policy and maternal complications. Population-attributable fractions (PAF) were conducted to quantify the maternal complications burden attributable to the implementation of the universal two-child policy. Results In the context of the universal two-child policy, the incidence of maternal near miss, antepartum or intrapartum complication, and post-partum complication increased at municipal- and county-level sample facilities. After adjusting for covariables, there were significant associations between the universal two-child policy and maternal risk factors ( P