In a study of 802 women in early pregnancy and a diagnosis of gestational diabetes, immediate treatment before 20 weeks’ gestation was more effective than no immediate treatment for preventing a composite of adverse neonatal outcomes. “On the basis of the 95% confidence interval around the estimated difference, the results were compatible with anywhere from a 1.2 to a 10.1 percentage-point reduction in the risk of an adverse neonatal outcome event,” the authors write. However, 2 other primary outcomes (pregnancy-related hypertension and neonatal lean body mass) showed no difference, and secondary outcomes were not significantly different between the groups.
Conducted in Australia, Austria, Sweden, and India, the Treatment of Booking Gestational Diabetes Mellitus (TOBOGM) trial included women between 4 weeks’ and 19 weeks 6 days’ gestation who had a risk factor for hyperglycemia and a diagnosis of gestational diabetes. They were randomized to immediate treatment for gestational diabetes or deferred or no treatment, depending on the results of a repeat oral glucose-tolerance test [OGTT] at 24 to 28 weeks’ gestation (control). The trial used 3 primary outcomes: a composite of adverse neonatal outcomes (birth at <37 weeks’ gestation, birth trauma, birth weight of ≥4500 g, respiratory distress, phototherapy, stillbirth or neonatal death, or shoulder dystocia), pregnancy-related hypertension (preeclampsia, eclampsia, or gestational hypertension), and neonatal lean body mass.
Among 793 women with follow-up data, the investigators found: “An initial OGTT was performed at a mean (± SD) gestation of 15.6 ± 2.5 weeks. An adverse neonatal outcome event occurred in 94 of 378 women (24.9%) in the immediate-treatment group and in 113 of 370 women (30.5%) in the control group (adjusted risk difference, −5.6 percentage points; 95% confidence interval [CI], −10.1 to −1.2). Pregnancy-related hypertension occurred in 40 of 378 women (10.6%) in the immediate-treatment group and in 37 of 372 women (9.9%) in the control group (adjusted risk difference, 0.7 percentage points; 95% CI, −1.6 to 2.9). The mean neonatal lean body mass was 2.86 kg in the immediate-treatment group and 2.91 kg in the control group (adjusted mean difference, −0.04 kg; 95% CI, −0.09 to 0.02). No between-group differences were observed with respect to serious adverse events associated with screening and treatment.”
Editorial: “This well-conducted trial provides much needed information regarding the benefits and harms of screening for and treating gestational diabetes in early pregnancy,” an editorialist writes. “The modest benefits observed — coupled with the negative results of the [Early Gestational Diabetes Screening in the Gravid Obese Woman (EGGO)] trial — call into question current recommendations for early screening and treatment among high risk women.”