The Effect of Midpregnancy Screening for Gestational Diabetes Mellitus on Pregnancy Outcomes: The TESGO Randomized Controlled Trial

OBJECTIVE Newborns delivered by women with gestational diabetes mellitus (GDM) have accelerated intrauterine growth earlier than the current recommended screening period. We aimed to determine whether universal GDM screening using a single oral glucose intolerance test (OGTT) at 18–20 weeks’ gestation improves pregnancy outcomes compared with standard screening at 24–28 weeks’ gestation. RESEARCH DESIGN AND METHODS We conducted a dual-center, parallel, randomized controlled trial with a planned interim analysis in singleton pregnant women to compare the effect of midpregnancy screening for GDM at 18–20 weeks’ gestation and standard screening at 24–28 weeks’ gestation. GDM was universally screened and diagnosed using 75-g OGTTs and the International Association of the Diabetes and Pregnancy Study Groups criteria. The primary outcome was a composite measure of primary cesarean delivery, birth weight >90th percentile, neonatal hypoglycemia, cord serum C-peptide >90th percentile, gestational hypertension, preeclampsia, and birth trauma. RESULTS The trial was stopped early for futility after the interim analysis. Of the 967 women included in the intention-to-treat analysis, the primary outcome was not significantly different between the two groups. Neonatal hypoglycemia was significantly lower and neonatal adiposity in women with GDM was higher in the midpregnancy screening group compared with the standard screening group. Adverse event rates were similar between the two groups. CONCLUSIONS Advancing universal GDM screening to midpregnancy at 18–20 weeks’ gestation may not improve pregnancy outcomes, except for a reduction in neonatal hypoglycemia. Newborns of women diagnosed with GDM through midpregnancy screening had higher neonatal adiposity.