Study Population and Design
Data for this study come from a prospective cohort study of pregnant women with GDM, diagnosed by a 1-hour glucose challenge test value ≥ 200 mg/dl or by the Carpenter-Coustan criteria for the 3-hour 100-gram OGTT, in care at a single academic medical center in the United States. Details of the study have been published previously.14Briefly, postpartum women with recent GDM were recruited between January 2017 and July 2018 and were eligible for enrollment if they were 18 years of age and fluent in English or Spanish. Women were excluded if they intended to move outside of the state in the coming year, could not tolerate a 75-gram glucose tolerance test (e.g., women with a history of gastric bypass), or had a known hemoglinopathy. At 2 days postpartum, all participants underwent a 2-hour 75-gram OGTT. Participants and their providers were blinded to the results of this OGTT. Postpartum care was otherwise not altered. Women were contacted to receive an OGTT at 4-12 weeks postpartum, in accordance with current clinical guidelines. Participants were followed through 1 year postpartum. In this analysis we included women that had an HbA1C measure at 1 year postpartum (+/- 4 months) to assess glucose metabolism (n=203/300, 68%; Figure 1). All study participants provided written informed consent prior to data collection and ethical approval was provided by the Institutional Review Board Women and Infants Hospital in Providence, Rhode Island (IRB #836907).