Background: The fetuses of women with gestational diabetes mellitus are at risk for macrosomia and its attendant complications. The best method of achieving euglycemia in these women and reducing morbidity in their infants is not known. We compared the efficacy of postprandial and preprandial monitoring in achieving glycemic control in women with gestational diabetes.
Methods: We studied 66 women with gestational diabetes mellitus who required insulin therapy at 30 weeks of gestation or earlier. The women were randomly assigned to have their diabetes managed according to the results of preprandial monitoring or postprandial monitoring (one hour after meals) of blood glucose concentrations. Both groups were also monitored with fasting blood glucose measurements. The goal of insulin therapy was a preprandial value of 60 to 105 mg per deciliter (3.3 to 5.9 mmol per liter) or a postprandial value of less than 140 mg per deciliter (7.8 mmol per liter). Obstetrical data and information on neonatal outcomes were collected.
Results: The prepregnancy weight, weight gain during pregnancy, gestational age at the diagnosis of diabetes and at delivery, degree of compliance with therapy, and degree of achievement of target blood glucose concentrations were similar in the two groups. The mean (+/- SD) change in the glycosylated hemoglobin value was greater in the group in which postprandial measurements were used (-3.0 +/- 2.2 percent vs. 0.6 +/- 1.6 percent, P < 0.001) and the infants' birth weight was lower (3469 +/- 668 vs. 3848 +/- 434 g, P = 0.01). Similarly, the infants born to the women in the postprandial-monitoring group had a lower rate of neonatal hypoglycemia (3 percent vs. 21 percent, P = 0.05), were less often large for gestational age (12 percent vs. 42 percent, P = 0.01) and were less often delivered by cesarean section because of cephalopelvic disproportion (12 percent vs. 36 percent, P = 0.04) than those in the preprandial-monitoring group.
Conclusions: Adjustment of insulin therapy in women with gestational diabetes according to the results of postprandial, rather than preprandial, blood glucose values improves glycemic control and decreases the risk of neonatal hypoglycemia, macrosomia, and cesarean delivery.