Perinatal impact of the use of metformin and glyburide for the treatment of gestational diabetes mellitus.

Objective: To evaluate the perinatal impact of metformin and glyburide in the treatment of gestational diabetes mellitus (GDM).

Methods: A randomized clinical trial conducted from July 2008 until September 2010 studied 200 pregnant women with GDM who required adjunctive therapy to diet and physical activity. Patients were randomized to use metformin (n=104) or glyburide (n=96). The drugs were replaced by insulin when they reached the maximum dose without glycemic control. Assessed outcomes: weight and neonatal blood glucose.

Results: No difference was found (P>0.05) between the groups regarding maternal age, gestational age at inclusion, body mass index, glucose levels in oral glucose tolerance test (OGTT) 75 g and glycemic control. Difference was found in the number of previous pregnancies (2.84 vs. 2.47, P=0.04) and weight gain during pregnancy (7.78 vs. 9.84, P=0.04) in the metformin group and glyburide respectively. The perinatal results showed no difference (P>0.05) in the percentage of cesarean deliveries, gestational age at delivery, number of newborns large for gestational age (LGA), neonatal hypoglycemia, admission to intensive care unit and perinatal death. We found differences in weight (3193 g vs. 3387 g, P=0.01) and ponderal index (2.87 vs. 2.96, P=0.05) of newborns, and in neonatal blood glucose levels at the 1st (59.78 vs. 54.08, P=0.01) and 3rd h (61.53 vs. 55.89, P=0.01) after birth between the metformin and glyburide groups respectively.

Conclusions: Weight and ponderal index were lower in the newborns of the metformin group; glucose levels (1st and 3rd h after birth) were lower in the glyburide group.