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

Objective: To determine whether polycystic ovary syndrome (PCOS) increases adverse pregnancy and birth outcomes in women undergoing frozen embryo transfer (FET).

Design: Retrospective cohort study. The PCOS group was matched 1:2 with the control group population using propensity score matching.

Setting: Not 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.

Results: Women 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.