Prevalence, trends, and maternal–fetal outcomes in pregnant women with polycystic ovary syndrome in Chinese mainland

BACKGROUND: Epidemiological data and the impact of China's fertility policies on pregnant women with polycystic ovary syndrome (PCOS) are limited. This study aims to investigate the prevalence, trends, and maternal-fetal outcomes among Chinese pregnant women with PCOS. METHODS: We used nationwide data of 14,083,975 pregnant women (2012-2021) from China's National Maternal Near Miss Surveillance System, spanning 438 hospitals across 30 provinces and covering both urban and rural regions. Interrupted time series analysis was applied to explore trends during the universal two-child policy period. Poisson regression analyses were used to estimate the maternal and fetal risks associated with PCOS. RESULTS: Among these pregnancies, 5.10 per 10,000 pregnant women were diagnosed with PCOS. The prevalence of PCOS increased from 0.79 per 10,000 in 2012 to 19.00 per 10,000 in 2021. Following the universal two-child policy, a relative increase of 0.23% (95% confidence interval 0.16-0.29%) was observed. Prevalence was higher in Eastern China (8.10 per 10,000), multiple pregnancies (34.00 per 10,000), women aged 30-34 years (8.10 per 10,000), and nulliparous women (8.00 per 10,000), with notable upward trends in all groups (Pfor trend <0.001 for all). PCOS was associated with increased risks of diabetes, gestational hypertension, preeclampsia, superimposed preeclampsia, hemolysis, elevated liver enzymes, and low platelets syndrome, and cesarean section. Fetal risks included abortion, preterm birth, full-term low-birth-weight babies, macrosomia, and neonatal asphyxia. Subgroup analyses indicated that these risks were particularly pronounced in singleton pregnancies, women aged below 35 years, and nulliparous women. CONCLUSIONS: The prevalence of pregnant women with PCOS increased significantly, with notable regional variations. Women with PCOS had higher risks of adverse maternal-fetal outcomes, highlighting the need for tailored interventions to preserve maternal-fetal well-being for individuals with PCOS.