Incidence of postpartum glucose intolerance among women with gestational diabetes in Siriraj Hospital

Objectives: To determine the incidence of postpartum glucose intolerance among women with gestational diabetes (GDM) and its associated factors. Methods: A total of 110 GDM women who delivered at Siriraj Hospital were enrolled. A 2-hour 75-gram glucose tolerance test and were offered at 6-12 weeks postpartum to determine incidence of glucose intolerance, which include impaired glucose tolerance (IGT), and type 2 diabetes (T2DM). Demographic data, GDM risks and diagnosis data, and delivery data were collected. Incidence of glucose intolerance was estimated. Comparison was made between glucose intolerance groups to determine possible associated factors. Results: Mean age was 33.7±5.1 years, and 46% were nulliparous. According to pre-pregnancy BMI, 45.5% were overweight/obese, and 24.5% gained weight greater than recommendation. Majority was GDM A1 (85.5%), and 63.6% were diagnosed before 20 weeks of gestation. Mean postpartum follow up time was at 6.2 ± 0.9 weeks. Incidence of postpartum IGT and T2DM were 35.5% and 10% respectively. No difference was found between groups in terms of pre-pregnancy BMI, gestational weight gain, weight retention, and severity of GDM. However, HbA1c level was significantly greater among women with postpartum T2DM than IGT and normal results (6.1±0.5%, 5.6±0.4%, and 5.4±0.3% respectively, p 6% significantly increased the chance of T2DM (33.3% vs. 53.4%, p=0.001). Conclusion: Among GDM pregnant women, incidence of postpartum glucose intolerance was 45.5% (35.5% IGT and 10% T2DM). HbA1c level of >6% significantly increased the chance of postpartum T2DM.