Adverse pregnancy outcomes following COVID-19 infection or vaccination in active component U.S. military service women, 2021-2023.

Prior studies have found a higher risk of adverse pregnancy outcomes due to COVID-19 infection; however, recent literature documents few adverse impacts to younger and otherwise healthy populations, but with limited information about military members. The study population comprised active component service women with a singleton delivery between 2021 and 2023. Adverse pregnancy outcomes were evaluated by COVID-19 infection and vaccination history, as well as by demographics and pre-existing comorbidities. During the surveillance period, 39,355 active component U.S. service women had a singleton delivery. After controlling for potential confounders in the adjusted logistic regression analysis, COVID-19 infection during pregnancy was associated with eclampsia (OR 2.18, p<0.05) and antepartum hemorrhage (OR 1.11, p<0.05), and COVID-19 infection prior to the start of pregnancy was associated with antepartum hemorrhage (OR 1.18, p<0.05). In comparison, after adjustment, COVID-19 vaccination during pregnancy and prior to start of pregnancy was not associated with increased odds of any adverse pregnancy outcome in active component service women. COVID-19 vaccines are recommended for pregnant women by the American College of Obstetricians and Gynecologists and, previously, the U.S. Centers for Disease Control and Prevention. This analysis found no significant difference in adverse pregnancy outcomes among those who received a COVID-19 vaccine prior to delivery compared to women who did not, between 2021 and 2023. COVID-19 infection prior to start of pregnancy was associated with antepartum hemorrhage whereas COVID-19 infection during pregnancy was associated with eclampsia and antepartum hemorrhage. The findings from this analysis suggest there is a benefit to vaccinating pregnant active component service women against COVID-19. There was no increased risk of these adverse pregnancy outcomes associated with receipt of a COVID-19 vaccine in this study population. In contrast, COVID-19 infection may be associated with increased occurrence of some adverse pregnancy events.