Determination of the Contributing Factors and HbA1c Cutoff Leading to Glucose Tolerance Abnormalities Following Gestational Diabetes.

Abstract

The prevalence of gestational diabetes mellitus (GDM) has been steadily increasing over the past years. It is a major risk factor for glucose intolerance and type 2 DM (T2DM). The American Diabetes Association recommends that women whose pregnancy was complicated by GDM be screened for persistent glucose abnormalities at six to 12 weeks postpartum with either a fasting plasma glucose test alone or with a fasting 75-g, two-hour oral glucose tolerance test. This study aimed to identify the main predictive factors of glucose tolerance disorders in early postpartum women with a recent history of GDM. In this retrospective descriptive study, we identified 400 women who met the eligibility criteria for the study. The mean age was 34.54 ± 5.51 years. A total of 70% had a family history of DM, 16% had a personal history of GDM, and 23% had fetal macrosomia in previous pregnancies. The overall incidence of postpartum carbohydrate tolerance disorders was 36.4%, including 12% prediabetes and 24.4% DM. The prevalence of prediabetes and T2DM after delivery was higher with older maternal age, multigravidity, a higher BMI, a history of GDM, and fetal macrosomia in previous pregnancies. Furthermore, the persistence of this impaired glucose tolerance in postpartum was associated with a higher term of diagnosis, a higher glycated hemoglobin (HbA1c) percentage (the discriminant cutoff value with the best sensitivity/specificity ratio was 5.25%), the use of insulin therapy, cesarean section delivery, and fetal macrosomia. After adjusting for confounders, only prior GDM, a higher HbA1c level, macrosomia, and gestational term were found to significantly affect postpartum glucose tolerance. Although postpartum screening for T2DM is recommended for all women with GDM, a significant number of patients fail it. A better knowledge of predictive factors for this outcome is therefore needed for a more effective and targeted medical intervention.