The Effect of Mid-pregnancy 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 if universal GDM screening at 18-20 weeks’ gestation improves pregnancy outcomes compared with standard screening at 24-28 weeks’ gestation, using a single oral glucose intolerance test (OGTT). Research Design and Methods: We conducted a dual-center parallel randomized controlled trial with a planned interim analysis in singleton pregnant women comparing the effect of mid-pregnancy screening for GDM at 18-20 weeks’ gestation and standard screening at 24-28 weeks’ gestation. GDM was universally screened and diagnosed using 75g OGTTs and the International Association of the Diabetes and Pregnancy Study Groups criteria. The primary outcome was a composite measure of primary cesarean section, birth weight >90th percentile, neonatal hypoglycemia, cord serum C-peptide >90th percentile, gestational hypertension, preeclampsia, and birth trauma. This trial is registered with ClinicalTrials.gov (NCT03523143). 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 mid-pregnancy screening group compared with the standard screening group. Adverse event rates were similar between the two groups. Conclusions: Advancing universal GDM screening to mid-pregnancy at 18-20 weeks’ gestation may not improve pregnancy outcomes, except for a reduction in neonatal hypoglycemia. Newborns of women diagnosed with GDM through mid-pregnancy screening had higher neonatal adiposity.