Polycystic ovary syndrome and risk of adverse pregnancy outcomes: a registry linkage study from Massachusetts

STUDY QUESTION: Do women with polycystic ovary syndrome (PCOS) have a greater risk of adverse pregnancy complications (gestational diabetes, preeclampsia, cesarean section, placental abnormalities) and neonatal outcomes (preterm birth, small for gestational age, prolonged delivery hospitalization) compared to women without a PCOS diagnosis and does this risk vary by BMI, subfertility and fertility treatment utilization? SUMMARY ANSWER: Deliveries to women with a history of PCOS were at greater risk of complications associated with cardiometabolic function, including gestational diabetes and preeclampsia, as well as preterm birth and prolonged length of delivery hospitalization. WHAT IS KNOWN ALREADY: Prior research has suggested that women with PCOS may be at increased risk of adverse pregnancy outcomes. However, findings have been inconsistent possibly due to lack of consistent adjustment for confounding factors, small samples size and other sources of bias. STUDY DESIGN, SIZE, DURATION: Massachusetts deliveries among women ≥18 years old during 2013–2017 from state vital records linked to hospital discharges, observational stays and emergency department visits were linked to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System (SART CORS) and the Massachusetts All-Payers Claims Database (APCD). PARTICIPANTS/MATERIALS, SETTING, METHODS: PCOS was identified by ICD9 and ICD10 codes in APCD prior to index delivery. Relative risks (RRs) and 95% CI for pregnancy and delivery complications were modeled using generalized estimating equations with a log link and a Poisson distribution to take multiple cycles into account and were adjusted a priori for maternal age, BMI, race/ethnicity, education, plurality, birth year, chronic hypertension and chronic diabetes. Tests for homogeneity investigated differences between maternal pre-pregnancy BMI categories (<30, ≥30, <25 and ≥25 kg/m²) and between non-infertile deliveries and deliveries that used ART or had a history of subfertility (defined by birth certificates, SART CORS records, APCD or hospital records). MAIN RESULTS AND THE ROLE OF CHANCE: Among 91 825 deliveries, 3.9% had a history of PCOS. Women with a history of PCOS had a 51% greater risk of gestational diabetes (CI: 1.38–1.65) and a 25% greater risk of preeclampsia (CI: 1.15–1.35) compared to women without a diagnosis of PCOS. Neonates born to women with a history of PCOS were more likely to be born preterm (RR: 1.17, CI: 1.06–1.29) and more likely to have a prolonged delivery hospitalization after additionally adjusting for gestational age (RR: 1.23, CI: 1.09–1.40) compared to those of women without a diagnosis of PCOS. The risk for gestational diabetes for women with PCOS was greater among women with a pre-pregnancy BMI <30 kg/m². LIMITATIONS, REASONS FOR CAUTION: PCOS was defined by ICD documentation prior to delivery so there may be women with undiagnosed PCOS or PCOS diagnosed after delivery included in the unexposed group. The study population is limited to deliveries within Massachusetts among most private insurance payers and inpatient or observational hospitalization in Massachusetts during the follow-up window, therefore there may be diagnoses and or deliveries outside of the state or outside of our sample that were not captured. WIDER IMPLICATIONS OF THE FINDINGS: In this population-based study, women with a history of PCOS were at greater risk of pregnancy complications associated with cardiometabolic function and preterm birth. Obstetricians should be aware of patients’ PCOS status and closely monitor for potential pregnancy complications to improve maternal and infant perinatal health outcomes. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the NIH (R01HD067270). S.A.M. receives grant funding from NIH, AbbVie and the Marriot Family Foundation; payment/honoraria from the University of British Columbia, World Endometriosis Research Foundation and Huilun Shanghai; travel support for attending meetings for ESHRE 2019, IASP 2019, National Endometriosis Network UK meeting 2019; SRI 2022, ESHRE 2022; participates on the data safety monitoring board/advisory board for AbbVie, Roche, Frontiers in Reproductive Health; and has a leadership role in the Society for Women’s Health Research, World Endometriosis Research Foundation, World Endometriosis Society, American Society for Reproductive Medicine and ESHRE. The other authors have no conflicts of interest.