Sulphoylurea drugs are contraindicated in pregnancy and gestational diabetes. Early experience of sulphonylureas in pregnancy resulted in neonates with prolonged hyperinsulinaemic hypoglycaemia and animal studies demonstrated direct toxic and teratogenic effects.
Glyburide is a sulphonylurea that does not seem to cross the placenta and a randomised controlled trial in 404 women with gestational diabetes gave successful results in 96% without any of the feared complications. Women began the therapy after 11 weeks of pregnancy so it was not possible to address concerns over teratogenicity and the study was also insufficiently powered to examine fetal or perinatal mortality.
Last reviewed 01/2018