Perinatal Outcomes of Two Screening Strategies for Gestational Diabetes Mellitus: A Randomized Controlled Trial.

OBJECTIVE

To evaluate differences in short-term perinatal outcomes between the two prominent screening strategies for gestational diabetes mellitus, the International Association of Diabetes and Pregnancy Study Groups (IADPSG) and Carpenter-Coustan.

METHODS

In this single-site, blinded, randomized, comparative effectiveness trial, participants received a nonfasting 50-g oral glucose tolerance test and, if less than 200 mg/dL (less than 11.1 mmol/L), were randomized to further screening with either IADPSG or Carpenter-Coustan criteria. Gestational diabetes treatment occurred per routine clinical care. The primary outcome was incidence of large-for-gestational-age (LGA) neonates. Prespecified secondary outcomes included small-for-gestational-age (SGA) neonates, cesarean birth, and neonatal and maternal composites of adverse perinatal outcomes. Assuming a 15% incidence of LGA neonates in the Carpenter-Coustan group, 782 participants provided more than 80% power to detect a 7% absolute risk reduction with the use of IADPSG; planned recruitment was 920 for anticipated attrition.

RESULTS

From June 2015 to February 2019, 1,016 participants were enrolled and 921 were randomized to IADPSG (n=461) or Carpenter-Coustan (n=460) groups. Gestational diabetes incidence (14.4% vs 4.5%, P<.001) and diabetes medication use (9.3% vs 2.4%; P<.001) were more common in the IADPSG group; there were no differences in LGA neonates, either overall (risk reduction 0.90, 97.5% CI 0.53-1.52) or among women without gestational diabetes (risk reduction 0.85, 97.5% CI 0.49-1.48). Those screened with IADPSG had higher rates of neonatal morbidity but fewer study-related adverse events. Rates of SGA neonates, cesarean birth, and maternal morbidity composite did not differ significantly between study groups.

CONCLUSIONS

The IADPSG screening criteria resulted in more women diagnosed and treated for gestational diabetes than Carpenter-Coustan without reducing the incidence of LGA birth weight or maternal or neonatal morbidity.

CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02309138.