Risk of Gestational Diabetes in Women With PCOS Based on Body Mass Index: The Japan Environment and Children's Study

Abstract Context Women with polycystic ovary syndrome (PCOS), which is the most common endocrine disorder in women of reproductive age, have a potentially increased risk of gestational diabetes mellitus (GDM). Objective To examine the impact of PCOS on GDM based on maternal body mass index (BMI) using data from a large birth cohort study in Japan. Design Prospective observational study using data from the Japan Environment and Children's Study (JECS). Participants Singleton pregnancies in the JECS during 2011-2014 were included. Mothers with HbA1c levels of ≥6.5% in the first trimester and history of diabetes mellitus or steroid use during pregnancy were excluded. Main Outcome Measures Participants were categorized according to their prepregnancy BMIs: G1 (18.5 kg/m2), G2 (18.5-19.99 kg/m2), G3 (20.0-22.99 kg/m2), G4 (23.0-24.99 kg/m2), and G5 (≥25.0 kg/m2). The impact of PCOS on early(Ed) and late-onset(Ld) GDM for each group was estimated using a multiple logistic regression model. Results We included 92 774 participants, comprising 2012 PCOS(+) cases. GDM occurrence was higher in women with PCOS (P .001). PCOS had no effect on GDM in G1, G2, and G3. In G4, PCOS increased the risk of Ed GDM (adjusted odds ratio aOR: 3.27; 95% confidence interval CI, 1.29-8.29). In G5, PCOS increased the risk of both Ed (aOR: 2.48; 95% CI, 1.53-4.02) and Ld GDM (aOR: 1.94; 95% CI, 1.23-3.07). Conclusion The impact of PCOS on GDM occurrence depended on the prepregnancy BMIs, which may facilitate personalized preconception counseling among women with PCOS.