Causes of perinatal mortality and risk factors in a district of Shanghai after the implementation of universal two-child policy

Objective To determine the changing trend and causes of perinatal mortality in Changning District after the implementation of the universal two-child policy， and then explore effective interventions for preventing perinatal mortality.

Methods Data of perinatal mortality in Changning District from 2011 to 2020 were retrospectively collected. Change of perinatal mortality， causes of death and related factors were compared in consecutive 5 years before and after the universal two-child policy.

Results In total， there were 153 099 perinatal births from 2011 to 2020 in Changning District， in which 352 deaths were documented. The perinatal mortality was 2.30 per 1 000 births， showing an overall downward trend from 2011 to 2020 （P<0.05）. Residents with local household registration had lower perinatal mortality， compared to those with non-local household registration， which was observed both before and after the universal two-child policy （P<0.05）. Furthermore， the perinatal mortality showed an upward trend after the universal two-child policy （χ²_trend=5.481， P<0.05）. The major causes of perinatal death were fetus and its accessories， fetal malformation， and maternal diseases during pregnancy before the universal two-child policy； in contrast， the causes changed to maternal diseases during pregnancy， fetus and its accessories， and neonatal diseases after the policy. The proportion of pregnant women of advanced maternal age， menstrual delivery， and pregnancy complications or comorbidities were significantly higher after the policy than that before the policy （P<0.05）. The most common pregnancy complication was gestational diabetes mellitus， gestational hypertension， and hypothyroidism during pregnancy after the universal two-child policy. Of them， the proportion of gestational hypertension increased from 6.56% （4/61） to 25.88% （22/85）.

Conclusion Before and after the universal two-child policy， the perinatal mortality in non-local residents remains high and further shows an upward trend. Moreover， pregnant women advanced maternal age and those with complications or comorbidities may increasingly contribute to perinatal deaths after the policy. Therefore， health education should be strengthened to improve the awareness of self-health care， especially for non-local women. Hierarchical perinatal health service， primary prevention and treatment of pregnancy complications or comorbidities should be improved to further reduce perinatal mortality.