Objective: To present the results of early postpartum metabolic assessment in women with gestational diabetes mellitus (GDM), to determine predictive factors for subsequent diabetes, and to investigate the association of postpartum glucose tolerance with other components of the metabolic syndrome.
Research design and methods: A total of 788 women were evaluated 3-6 months after a GDM pregnancy. A 75-g oral glucose tolerance test (OGTT) was performed. Cholesterol, HDL cholesterol, triglycerides, blood pressure, BMI, and body fat distribution were assessed. Clinical and obstetric history, baseline variables at the diagnosis of GDM, metabolic control during pregnancy, and index pregnancy outcome were compared in women with diabetes and women without diabetes (American Diabetes Association [ADA] criteria) after pregnancy. Multivariate logistic regression analysis was used to ascertain independent predictors of subsequent diabetes. Correlation coefficients were assessed between postpartum glucose tolerance and lipid levels, blood pressure, BMI, and body fat distribution.
Results: According to ADA criteria, 588 (74.6%) women were normal, 46 (5.8%) had impaired fasting glucose, 82 (10.4%) had impaired glucose tolerance, 29 (3.7%) had both impaired fasting glucose and impaired glucose tolerance, and 43 (5.4%) had diabetes. Prepregnancy obesity, recurrence of GDM, gestational age at diagnosis of GDM, glucose values in the 100-g OGTT, number of abnormal values in the 100-g OGTT, fasting C-peptide levels in pregnancy, C-peptide/glucose score in pregnancy, insulin requirement in pregnancy, 3rd trimester HbA1c levels, and macrosomia differed significantly in women with subsequent diabetes. Independent predictors of postpartum diabetes were prepregnancy obesity, C-peptide/glucose score during pregnancy, and the number of abnormal values in the 100-g diagnostic OGTT. The area under the postpartum glucose curve was positively associated with BMI, waist circumference, waist-to-hip ratio, triglycerides, and systolic and diastolic blood pressures.
Conclusions: Low C-peptide/glucose score during pregnancy together with prepregnancy obesity and severity of GDM (number of abnormal values in the 100-g diagnostic OGTT) are independent predictors of subsequent diabetes. Our data suggest that regardless of obesity and severity of GDM, a beta-cell defect increases the risk of postpartum diabetes. The association of postpartum glucose tolerance with triglyceride levels, blood pressure, obesity, and regional distribution of body fat suggests that postpartum glucose intolerance anticipates a high-risk cardiovascular profile that comprises other risk factors besides diabetes.