Gestational Diabetes—Screening, Prevalence and Postpartum Diabetes: Population-Based Cohort Study

Aims: To evaluate GDM screening compliance and prevalence, and the association between gestational glucose intolerance and 5-year postpartum diabetes mellitus (DM). Materials and Methods: We used population-based data from three Israeli health maintenance organisations (HMOs), covering 75% of all births in 2016. GDM screening followed a two-step approach: a 50-g 1-h oral glucose challenge test (OGCT), followed by a 100-g 3-h oral glucose tolerance test (OGTT) using Carpenter-Coustan criteria. Data included age, socioeconomic status (SES), results of OGCT and OGTT tests, child birth weight, and gestational age. The dataset was linked to the Israeli National Diabetes Registry to identify postpartum DM. Logistic regression models estimated odds ratios (ORs) for GDM and postpartum DM, adjusting for maternal age, SES, ethnicity, and glucose tolerance status. Results: Among 128,454 women, 10% were unscreened. Of those screened, 23,451 underwent the full OGTT. GDM prevalence was 4.3%. Postpartum DM incidence was 8.6% in women with GDM, 3.1% with unknown GDM status, and 2.1% with impaired glucose tolerance (IGT) (defined as one abnormal value on the OGTT). Compared with normoglycemia, adjusted ORs for the 5-year postpartum DM were 25.48 (95% CI: 21.80–29.79) for GDM, 10.04 (95% CI: 8.59–11.74) for unknown GDM status, 6.48 (95% CI: 5.07–8.28) for IGT, and 2.17 (95% CI: 1.63–2.88) for abnormal OGCT with normal OGTT. Older age, lower SES, and Arab or Bedouin ethnicity were linked to higher GDM and postpartum DM. Conclusions: Gestational glucose intolerance and screening gaps were strong predictors of postpartum DM. Age, SES, and ethnicity highlight the need for targeted efforts to reduce health disparities.