Objectives
Evaluate peripartum outcomes following COVID-19 vaccination during pregnancy.
Methods
Ontario population-based retrospective cohort between December 14, 2020 and September 30, 2021 using linkage of provincial birth registry and COVID-19 immunization databases. Poisson regression was used to generate risk ratios (RR) and 95% confidence intervals (CI), adjusted for temporal, socio-demographic, and clinical factors using propensity scores. Obstetric (postpartum hemorrhage, chorioamnionitis, cesarean birth) and newborn (NICU admission and 5-minute Apgar<7) outcomes were compared for those who received ≥1 dose of COVID-19 vaccine during pregnancy with 2 unexposed groups—Group 1: individuals vaccinated postpartum, Group 2: never vaccinated.
Results
Among 97 590 individuals, 22 660 (23%) received ≥1 dose of vaccine during pregnancy (64% received dose 1 in 3rd trimester). Compared with those vaccinated postpartum, we found no increased risks of postpartum hemorrhage (aRR 0.91, 95% CI 0.82–1.02); chorioamnionitis (aRR 0.92, 95% CI 0.70–1.21); or cesarean (aRR 0.92, 95% CI 0.89–0.95) following COVID-19 vaccination, nor any increased risk of NICU admission or 5-minute Apgar <7. All findings were similar when compared with individuals who did not receive COVID-19 vaccination at any point. We did not observe any difference according to vaccine product, number of doses received during pregnancy, or trimester of dose 1.
Conclusions
As of late 2021, there is limited evidence from comparative studies in large populations on outcomes following COVID-19 vaccination during pregnancy. Our study of births up to September 30, 2021 did not identify any increased adverse peripartum outcomes associated with later pregnancy COVID-19 vaccination. Once more individuals vaccinated earlier in pregnancy deliver, we will report on other important obstetric and perinatal outcomes.
Keywords
COVID-19 vaccine; pregnancy; epidemiology
Article info
Identification
Copyright
© 2022 Published by Elsevier Inc.
