Maternal and Neonatal Outcomes in Pregnant Women Vaccinated Against COVID-19 Compared to an Unvaccinated Group

Immunizing pregnant women against COVID-19 is crucial due to their heightened risk of severe outcomes. However, data on vaccination's clinical effects during pregnancy are limited. This study evaluated maternal and neonatal outcomes in vaccinated pregnant women, stratified by vaccine doses, compared to unvaccinated controls.

This retrospective cohort study analyzed pregnant women without a history of COVID-19 infection who delivered at Amir-Al-Momenin Hospital in Semnan, Iran (2020-2022). Data on demographics, obstetric history, vaccination status, maternal complications, and neonatal outcomes were extracted from hospital records.

The cohort included 300 vaccinated and 104 unvaccinated women with comparable baseline characteristics. Overall maternal complication rates were similar between groups (41.0% vs 44.2%). However, miscarriage was reported in 12/300 (4.0%) vaccinated women compared to 0/104 (0%) in the unvaccinated group (p=0.038). No other maternal outcomes differed significantly. Neonatal 5-minute Apgar scores were slightly lower in the vaccinated group (mean difference -0.25, 95% CI [-0.48 to -0.02]; p=0.031). Conversely, intrauterine growth restriction (IUGR) was significantly less frequent in neonates born to vaccinated mothers (2.0% vs 9.6%; Odds Ratio 0.19, 95% CI [0.07 to 0.54]; p=0.005). The number of vaccine doses received was not associated with maternal or neonatal outcomes.

In this single-center cohort, COVID-19 vaccination during pregnancy was not associated with an overall increase in adverse maternal complications and was linked to a lower risk of neonatal IUGR. However, the findings also indicated a higher incidence of miscarriage and slightly lower 5-minute Apgar scores in the vaccinated group, which warrant further investigation. These results, while largely reassuring, highlight the need for continued surveillance and larger studies to fully characterize the safety profile of COVID-19 vaccines in pregnancy.