A Multicenter, Randomized Trial of Treatment for Mild Gestational Diabetes

Abstract

Although there is little evidence that the screening, identification, and treatment of mild gestational diabetes during pregnancy is beneficial, a number of professional organizations have recommended screening for this disorder in most pregnant women. The aim of this multicenter randomized trial was to determine whether treatment of women with mild gestational diabetes mellitus reduces perinatal and obstetrical complications. The participants were 958 women between 24 and 31 weeks of gestation who met criteria for mild gestational diabetes mellitus. They were randomly assigned to receive either formal nutritional counseling, diet therapy, and self-monitoring of blood glucose, together with insulin if required (treatment group, n = 485) or usual prenatal care (control group, n = 473). The primary study outcome was a composite outcome that included perinatal mortality (stillbirth or neonatal death) and neonatal complications that have been associated with maternal hyperglycemia: hypoglycemia, hyperbilirubinemia, neonatal hyperinsulinemia, and birth trauma. There was no significant difference between the 2 groups in the frequency of the composite primary perinatal outcomes of mortality and neonatal complications (treatment group: 32.4% and control group: 37.0%, respectively; the relative risk was 0.87, with a 97% confidence interval of 0.72–1.07; P = 0.14). However, compared with usual care, treatment was associated with significant reductions in several prespecified secondary neonatal or maternal outcomes including mean birth weight (3408 vs. 3302 g), neonatal fat mass (464 vs. 427 g), the frequency of large-for-gestational age infants (14.5% vs. 7.1%), birth weight greater than 4000 g (14.3% vs. 5.9%), shoulder dystocia (4.0% vs. 1.5%), and cesarean delivery (33.8% vs. 26.9%) (P < 0.02 for all comparisons). In addition, the frequency of the combined rates of preeclampsia and gestational hypertension was significantly lower in the treatment group (P < 0.01). These findings show that treatment of mild gestational diabetes mellitus is associated with a reduced risk of several secondary complications including fetal overgrowth, shoulder dystocia, cesarean delivery, and hypertensive disorders (preeclampsia and gestational hypertension).