Increasing Prevalence of Diagnosed Gestational Diabetes in South Carolina: 2015-2021

Objective: To examine trends with a focus on racial and ethnic disparities in reported gestational diabetes mellitus (GDM) and related outcomes (macrosomia, large for gestational age infants) before and during the COVID-19 pandemic in South Carolina (SC). Methods: A retrospective cohort study of pregnancies resulting in livebirths from 2015 through 2021 was conducted in SC. Statewide maternal hospital and emergency department discharge codes were linked to birth certificate data. GDM was defined by ICD-9-CM (i.e., 648.01-648.02, 648.81-648.82) or ICD-10-CM codes (i.e., O24.4, O24.1, O24.9), or indication of GDM on the birth certificate without evidence of diabetes outside pregnancy (ICD-9-CM: 250.xx; ICD-10-CM: E10, E11, O24.0, O24.1, O24.3). Results: Our study included 194,777 non-Hispanic White (White), 108,165 non-Hispanic Black (Black), 25,556 Hispanic, and 16,344 other race-ethnic group pregnancies. The relative risk for GDM associated with a 1-year increase was 1.01 (95% confidence interval [CI]: 1.01-1.02) before the pandemic and 1.12 (1.09-1.14) during the pandemic. While there were race-ethnic differences in the prevalence of GDM, increasing trends were similar across all race-ethnic groups before and during the pandemic. From quarter 1, 2020, to quarter 4, 2021, the prevalence of reported GDM increased from 8.92% to 10.85% in White, from 8.04% to 9.78% in Black, from 11.2% to 13.65% in Hispanic, and from 13.3% to 16.16% in other race-ethnic women. Conclusion: An increasing prevalence of diagnosed GDM was reported during the COVID-19 pandemic. Future studies are needed to understand the mechanisms underlying increasing trends, to develop interventions, and to determine whether the increasing trend continues in subsequent years.