Gestational and Pregestational Diabetes Screening Changes in Early Pregnancy and Perinatal Outcomes

To evaluate an initiative to decrease gestational diabetes (GDM) screening rates before 24 weeks of gestation and to increase early-pregnancy hemoglobin A 1C (Hb A 1C ) testing for undiagnosed pregestational diabetes and the association of this change with perinatal complications.

All patients with live births and without overt diabetes who delivered between 2018 and 2022 were included. We performed an interrupted time series analysis to examine perinatal outcomes associated with the recommended changes. To reflect the level of exposure to recommended changes that started April 2020, delivery dates were categorized into three time periods: T1, unexposed (January 1, 2018-March 31, 2020); T2, partially exposed (April 1-December 31, 2020); and T3, fully exposed (January 1, 2021-December 31, 2022). The primary outcome was a composite including large-for-gestational-age birth weight, cesarean delivery, preeclampsia, severe maternal morbidity, preterm birth, shoulder dystocia, neonatal hypoglycemia, and neonatal intensive care unit admission.

Among 221,068 delivering individuals, early GDM screening rates decreased from 31.1% in T1 to 20.6% in T2 and 4.3% in T3 (standardized mean difference [SMD] T3 vs T1, -0.75), and Hb A 1C testing increased from 12.3% to 23-35.2% (SMD T3 vs T1, 0.56). There was no change in the prevalence of the composite primary outcome: 43.1% in T1, 44.2% in T2, and 45.2% in T3 (SMD T3 vs T1, 0.04). Interrupted time series analysis adjusted for covariates showed no change in risk of the composite outcome during T1 (percent change/4 weeks, 0.06 [95% CI, -0.01 to 0.13]), T2 (0.02 [95% CI, -0.21 to 0.25]), or T3 (-0.02 [95% CI, -0.26 to 0.23]).

A decrease in early GDM screening accompanied by increased early Hb A 1C testing did not influence perinatal outcomes.