In this randomized trial of treatment versus no treatment for mild gestational diabetes mellitus, rates of the primary outcome (a composite of stillbirth or perinatal death and neonatal hyperbilirubinemia, hypoglycemia, hyperinsulinemia, or birth trauma) did not differ significantly between groups. However, there were significant reductions with treatment in several secondary outcomes, including the frequency of large-for-gestational-age infants, shoulder dystocia, cesarean delivery, and hyperte