Oral antihyperglycemic agents during pregnancy and lactation: a review

The treatment approach of diabetes mellitus during pregnancy requires a combination of diet, exercise, multiple home glucose determinations and intensive insulin regimens. During the last decade there was an increased interest in the use of oral antihyperglycemic agents (OAHAs) as an alternative to insulin in achieving good glycemic control. OAHAs are divided into four groups: derivatives of sulfonylurea, biguanides, glucosidase inhibitors and thiazolidinediones. This review describes the possible teratogenic effects of the use of OAHAs during pregnancy and the effects of these drugs during lactation. Animal and human studies assessing the teratogenic effects of OAHAs have yielded conflicting data because the risk of major malformations in infants of mothers with diabetes appears to be related to maternal glycemic control rather than the antidiabetic therapy. A major concern with the use of OAHAs during pregnancy is neonatal hypoglycemia, which may be severe and persist for days. Therefore, insulin is still the drug of choice because it has not been implicated as a teratogen in human pregnancies. In addition, because of the lack of data regarding the use of OAHAs in pregnancy, we cannot draw firm conclusions about all of the available drugs. However, OAHAs, especially glibenclamide (glyburide), may be beneficial in a situation where the proper use of insulin is problematic. Because there are very limited clinical data on the exposure of OAHAs to the infant via breast milk, and the potentially serious effect of neonatal hypoglycemia, the safest recommendation is not to breast feed while taking OAHAs. Well-conducted, prospective, controlled studies regarding the feasibility of OAHAs in pregnant women with diabetes and during lactation are needed.