Association Between SARS-CoV-2 Infection During Pregnancy and Gestational Diabetes: A Claims-based Cohort Study.

Introduction: Coronavirus disease 2019 (COVID-19) may be associated with gestational diabetes mellitus (GDM); however, evidence is limited by sample sizes and lack of control groups.

Methods: To assess the GDM risk after COVID-19 in pregnancy, we constructed a retrospective cohort of pregnancies ending March 2020-October 2022 using medical claims. People with COVID-19 diagnosis claims from conception to 21 gestational weeks (n = 57 675) were matched 1:2 to those without COVID-19 during pregnancy (n = 115 350) by age range, pregnancy start month, and encounter year-month. GDM (claim ≥23 gestational weeks) relative risk and risk difference overall, by race and ethnicity, and variant period were estimated using log-binomial models.

Results: GDM risk was higher among those with COVID-19 during pregnancy compared to those without (adjusted risk ratio [aRR] = 1.12; 95% confidence interval [CI], 1.08-1.15). GDM risk was significantly associated with COVID-19 in non-Hispanic White (aRR = 1.08; 95% CI, 1.04-1.14), non-Hispanic Black (aRR = 1.15; 95% CI, 1.07-1.24), and Hispanic (aRR = 1.17; 95% CI, 1.10-1.24) groups. GDM risk was significantly higher during pre-Delta (aRR = 1.17; 95% CI, 1.11-1.24) compared to Omicron (aRR = 1.07; 95% CI, 1.02-1.13) periods, but neither differed from the Delta period (aRR = 1.10; 95% CI, 1.04-1.17). The adjusted risk difference was 0%-2% for all models.

Conclusions: COVID-19 during pregnancy was modestly associated with GDM in claims-based data, especially during earlier SARS-CoV-2 variant periods. Because these associations are based on COVID-19 in claims data, studies employing systematic testing are warranted.