Abnormal glucose tolerance in women with prior gestational diabetes mellitus: a 4-year follow-up study.

BACKGROUND: Adoption of the International Association of Diabetes and Pregnancy Study Group (IADPSG) criteria for diagnosis of gestational diabetes mellitus (GDM) varies worldwide. Early detection of women at increased risk of developing type 2 diabetes mellitus (T2DM) following GDM enables initiation of measures to delay disease onset. OBJECTIVES: To determine the 4-year cumulative incidence and risk factors for developing abnormal glucose tolerance (AGT) among women with previous GDM using modified IADPSG criteria. Additionally, to review post-natal attendance at diabetes screening and the impact of post-partum lifestyle modifications and breastfeeding on the risk of T2DM development. METHODS: Four hundred twenty-six women with a prior history of GDM were invited to participate in the study, 4 years after the index pregnancy. The following were completed: body measurements, oral glucose tolerance test (OGTT), glycated haemoglobin (HbA1c), vitamin D, and other biochemistry measurements. Participants also completed a lifestyle questionnaire. RESULTS: Of the 74 women who participated, 15 (20%) had AGT. Predictive factors for AGT development were as follows: fasting glucose levels (p = 0.004), HbA1c (p = 0.008) at GDM diagnosis, and early pregnancy BMI (p = 0.001). Thirty-three (45%) women had not attended their postnatal screening. The odds ratio of the association between breastfeeding and AGT development was 0.16 (95% CI: 0.05 to 0.53). CONCLUSION: The proportion of women who develop AGT after a diagnosis of GDM remains high. The factors associated with progression to AGT are available at GDM diagnosis. Preventing AGT in this group is possible by supporting breastfeeding. Attendance at post-natal screening should also be encouraged.