Risk factors during the early postpartum period for type 2 diabetes mellitus in women with gestational diabetes

For women with gestational diabetes mellitus (GDM), the evaluation of glucose tolerance (GT) in the early postpartum period is universally recommended. Nevertheless, few studies have evaluated the risk factors for T2DM on the basis of GT data obtained during the early postpartum period. We aimed to identify the risk factors for type 2 diabetes mellitus (T2DM) by evaluating GT in the first 12 weeks postpartum (12wPP) in women with GDM and to categorize the risk using a combination of the principal risk factors. This retrospective multicenter observational study included 399 East Asian women with GDM who underwent a 75-g oral glucose tolerance test (OGTT) within 12wPP, which was repeated annually or biennially and used to identify the postpartum development of T2DM. Forty-three women (10.8%) developed T2DM during a median follow-up period of 789 ± 477 days. The independent risk factors for T2DM were pre-pregnancy obesity (BMI ≥25 kg/m²), early postpartum impairment in glucose tolerance (IGT), and an early postpartum glycated hemoglobin (HbA1c) ≥5.7%. The odds ratios (95% confidence intervals) for T2DM were 3.2 (1.3–7.8) in women with either early postpartum IGT or pre-pregnancy obesity, 9.2 (3.0–28.3) in those with early postpartum IGT, pre-pregnancy obesity, and HbA1c <5.7%, and 51.4 (16.1–163.9) in those with early postpartum IGT, pre-pregnancy obesity, and HbA1c ≥5.7%, compared with those without obesity or IGT. T2DM risk in East Asian women with GDM should be stratified according to pre-pregnancy obesity and early postpartum IGT, and these patients should be followed up and receive appropriate care for their risk category.