Distinct pregnancy challenges in PCOS women undergoing IVF/ICSI with singleton and twin births: a propensity-matched analysis.

backgroundPolycystic ovary syndrome (PCOS) has been associated with adverse pregnancy outcomes; however, current literature presents inconsistent findings, probably due to varying feotal numbers included in previous research. This study sought to evaluate pregnancy outcomes in women with PCOS undergoing assisted reproductive technology (ART), with a specific focus on differentiating between singleton and twin births.

methodsThis cohort study included women who underwent in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) and maintained pregnancies beyond 20 weeks of gestation. Participants with PCOS or tubal factors were matched using 1:2 propensity score matching (PSM) separately within singleton and twin birth cohorts. Maternal and neonatal outcomes were collected from 95 hospitals and analysed using conditional logistic regression with cluster-robust standard errors (CRSEs) at hospital levels. Mediation analysis was further conducted to identify pathways between PCOS and several adverse outcomes.

resultsFrom 1 June 2017 to 31 May 2022, 696 PCOS women and 1392 controls with singleton births, as well as 201 PCOS women and 402 controls with twin births, were matched for final analysis. In singleton birth cohort, PCOS women were associated with hypertensive diseases of pregnancy [HDP; crude odds ratio (OR) = 1.91, P adjusted for multiple comparisons < 0.001, the same below], pre-eclampsia (PE; OR = 1.67, P < 0.01), and cervical incompetence (CIC; OR = 3.84, P < 0.001). In twin birth cohort, PCOS women had increased odds of gestational diabetes mellitus (GDM; OR = 2.23, P < 0.001) and very preterm birth (VPTB; OR = 2.08, P < 0.01), compared to their counterparts. No significant between-group differences were observed for preterm premature rupture of membranes (PPROM). The findings were consistent after regression adjustments, multiple comparison correction, subgroup analyses, and sensitivity analyses. Subsequent mediation analysis highlighted preconception BMI and insulin resistance (IR) as key mediators to PCOS-related HDP and PE for women with singleton births. Further exploratory analysis indicated several preconception prognostic factors of adverse pregnancy outcomes in PCOS, especially metabolic indicators.

conclusionsIn this study, women with PCOS who had singleton births demonstrated a higher incidence of hypertension and CIC compared to those with tubal factors. Among women with twin births, increased risks of GDM and VPTB were noted in addition to the inherent risks of twin gestation. Our findings contribute to the body of evidence regarding the differential pregnancy outcomes based on foetal number in PCOS women undergoing ART, highlighting the necessity of individual reproductive and obstetric management in clinical practice.