Delayed insulin secretion in the early postpartum period is associated with future abnormal glucose metabolism among women with a history of gestational diabetes mellitus: a prospective cohort study

OBJECTIVES: This study examined whether early postpartum insulin response patterns (< 6 months) following a glucose load predict the emergence of abnormal glucose metabolism (AGM) in women who were previously diagnosed with gestational diabetes mellitus (GDM). METHODS: We conducted a prospective cohort study involving 308 women who had prior GDM. A 75-gram oral glucose tolerance test was administered to each participant within six months after delivery, and the participant's insulin levels were measured at baseline, 30 min, and 2 h following glucose administration. Participants were categorized as having delayed insulin secretion (In2h ≥ In30min; n = 196) or a normal insulin response (In2h < In30min; n = 112). Over an average follow-up period of 32.7 months, Cox proportional hazards models were employed to assess adjusted hazard ratios for AGM development. RESULTS: Among the 308 women, 153 (49.7%) developed AGM. The delayed insulin secretion group faced a significantly elevated risk (adjusted HR 1.739 [95% CI 1.141-2.649], P = 0.010). Other significant risk factors included elevated fasting glucose levels during pregnancy (adjusted HR 1.565 [95% CI 1.152-2.125], P = 0.004) and early postpartum hypertriglyceridemia (adjusted HR 1.448 [95% CI 1.029-2.039], P = 0.034). CONCLUSIONS: A sluggish insulin response during the early postpartum phase is a robust predictor of future AGM in women with prior GDM.