A comparison of glyburide and insulin in women with gestational diabetes mellitus

Background Women with gestational diabetes mellitus are rarely treated with a sulfonylurea drug, because of concern about teratogenicity and neonatal hypoglycemia. There is little information about the efficacy of these drugs in this group of women. Methods We studied 404 women with singleton pregnancies and gestational dia betes that required treatment. The women were randomly assigned tween 11 an d 33 weeks of gestation to receive glyburide or insulin according to an int ensified treatment protocol. The primary end point was achievement of desir ed level of glycemic control. Secondary end points included maternal and ne onatal complications. Results The mean (+/-SD) pretreatment blood glucose concentration as measur ed at home for one week was 114 +/- 19 mg per deciliter (6.4 +/- 1. 1 mmol per liter) in the glyburide group and 116 +/- 22 mg per deciliter (6.5 +/- 1. 2 mmol per liter) in the insulin group (P = 0.33). The mean concentratio ns during treatment were 105 +/- 16 mg per deciliter (5.9 +/- 0.9 mmol per liter) in the glyburide group and 105 +/- 18 mg per deciliter (5.9 +/- 1. 0 per liter) in the insulin group (P = 0.99). Eight women in the glyburide g roup (4 percent) required insulin therapy. There were no significant differ ences between the glyburide and insulin groups in the percentage of infants who were large for gestational age (12 percent and 13 percent, respectivel y); who had macrosomia, defined as a birth weight of 4000 g or more (7 perc ent and 4 percent); who had lung complications (8 percent and 6 percent); w ho had hypoglycemia (9 percent and 6 percent); who were admitted to a neona tal intensive care unit (6 percent and 7 cent); or who had fetal anomalies (2 percent and 2 percent). The cord-serum insulin concentrations were simil ar in the two groups, and glyburide was not detected in the cord serum of a ny infant in the glyburide group. Conclusions In women with gestational diabetes, glyburide is a clinically e ffective alternative to insulin therapy. (N Engl J Med 2000; 343:1134-8.) ( C) 2000, Massachusetts Medical Society.