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

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).

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.

Prospective observational study using data from the Japan Environment and Children's Study (JECS).

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.

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.

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).

The impact of PCOS on GDM occurrence depended on the prepregnancy BMIs, which may facilitate personalized preconception counseling among women with PCOS.