Our hypothesis is that metformin and glyburide will have equal efficacy in controlling blood glucose in gestational diabetics with no increase in adverse maternal, fetal or neonatal outcomes.

Pregnant women are screened with a one hour 50g glucose challenge. Women with values of 130 mg/dl or greater are then given a 100g glucose tolerance test. Two abnormal values are diagnostic of gestational diabetes. all women are initially counseled on diet and exercise. Women who fail to maintain a fasting of <105mg/dl and 2 hr postprandial < 120 mg/dl are offered participation in the study. Women were randomized to either metformin or glyburide via a computer generated randomization. Women who fail to meet glycemic goals after receiving the maximum dose of study medication were considered treatment failures and insulin therapy was initiated.

Inclusion Criteria:

• Gestational diabetes not controlled with diet and exercise

Exclusion Criteria:

• history of alcohol misuse
• history of drug misuse
• Chronic hypertension requiring medication
• Renal failure
• Hepatic disease or dysfunction
• Known fetal anomaly
• Inability to give consent
• known allergy to metformin or glyburide

4 years