Early Metformin in Gestational Diabetes: A Randomized Clinical Trial

( JAMA . 2023;330(16):1547–1556. doi: 10.1001/jama.2023.19869) Gestational diabetes (gDM) is a common pregnancy complication, affecting up to nearly 3 million pregnancies globally every year. It is known to be associated with adverse pregnancy outcomes, including weight gain, cesarean delivery, preeclampsia, birth injuries, respiratory distress, and neonatal ICU admission. Optimal management of gDM is unclear. Current guidelines recommend lifestyle modifications with nutrition and exercise, and subsequent insulin administration if hyperglycemia persists. Although effective in improving outcomes, insulin is linked to increased hypoglycemia events, weight gain, cesarean delivery, and neonatal ICU admission. Metformin in pregnancy is also associated with improved maternal and fetal outcomes compared to insulin, although there are concerns relating to spontaneous preterm birth and small for gestational age infants. Though metformin is considered safe during pregnancy, it is currently only prescribed after lifestyle management failure; this study was designed to test the hypothesis that earlier administration of metformin upon diagnosis of gDM would be beneficial to the outcomes of mothers and babies, primarily assessing the effect on the composite of insulin initiation and fasting hyperglycemia at 32 or 38 weeks of gestation.