Changes in maternal age and prevalence of congenital anomalies during the enactment of China's universal two-child policy (2013-2017) in Zhejiang Province, China: An observational study.

In this study, we observed significant increases in maternal age and the prevalence of total and age-related anomalies following China's new two-child policy. Increases in live birth rate for infants with BDs born before 28 gestational weeks suggest that healthcare for very preterm births with BDs may be warranted in the future, as well as updating the definition of perinatal period.