Pregnancy complications and birth outcomes in women with polycystic ovary syndrome undergoing frozen embryo transfer

ObjectiveTo determine whether polycystic ovary syndrome (PCOS) increases adverse pregnancy and birth outcomes in women undergoing frozen embryo transfer (FET).DesignRetrospective cohort study. The PCOS group was matched 1:2 with the control group population using propensity score matching.SettingNot applicable.Patient(s)During an 8-year period, 2,955 patients aged 20–40 years who underwent FET and delivered between January 2015 and December 2022 at the Reproductive Medical Center of Ruijin Hospital were evaluated for adverse pregnancy outcomes.Intervention(s)None.Main Outcome Measure(s)All patients were assessed for specific pregnancy complications and birth outcomes, with a sub-group analysis conducted to compare patients with PCOS with and without hyperandrogenism.ResultsWomen with PCOS demonstrated higher rates of gestational diabetes mellitus (24.9% vs. 16.4%; relative risk RR, 1.51; 95% confidence interval CI, 1.26–1.82; P<.001), gestational hypertension (12.2% vs. 8.9%; RR, 1.37; 95% CI, 1.05–1.80; P=.022), preterm prelabor rupture of membranes (7.0% vs. 3.6%; RR, 1.92; 95% CI, 1.29–2.86; P=.001), cervical length shortening (1.8% vs. 0.4%; RR, 8.39; 95% CI, 1.56–12.49; P=.002), large-for-gestational age (17.4% vs. 13.7%; RR, 1.27; 95% CI, 1.02–1.57; P=.032), and low birth weight (19.9% vs. 16.0%; RR, 1.25; 95% CI, 1.02–1.52; P=.030) in overall propensity score matching analysis. Newborns of patients with PCOS had a higher risk of preterm birth <37 weeks (10.5% vs. 6.6%; RR, 1.59; 95% CI, 1.12–2.26; P=.009) in singleton pregnancies. Patients with PCOS with hyperandrogenism showed a higher incidence of cervical length shortening (5.5% vs. 0.5%; adjusted odds ratio, 15.62; 95% CI, 2.25–108.48; P=.005) compared with those without, after adjusting for relevant confounders.Conclusion(s)Polycystic ovary syndrome increases the incidence of adverse pregnancy outcomes after FET cycles. Our study suggests women with PCOS may warrant further monitoring and additional counseling before and during pregnancy.