In this cohort study of 11 321 patients with gestational diabetes, the use of glyburide vs insulin was associated with similar rates of infant hypoglycemia, hyperbilirubinemia, appropriate size-for–gestational age, and cesarean delivery as well as significantly lower rates of infant neonatal intensive care unit admission after adjusting for baseline and time-varying covariates. This evidence concerns the gene INS and gestational diabetes.