Safety of COVID-19 vaccination in pregnant women: A study of the adverse perinatal outcomes.

ABSTRACT

OBJECTIVE: To compare adverse perinatal outcome among COVID-19 vaccinated and unvaccinated pregnant women. METHOD: Retrospective equivalence cohort study comparing 930 women who received at least one BNT162b2 (Pfizer/BioNTech) COVID-19 vaccine during the second or third trimester of pregnancy and 964 unvaccinated women. The primary outcome was a composite adverse perinatal outcome including at least one of the following preterm delivery<35 weeks gestation; intrauterine fetal death>23 weeks gestation; intrauterine growth restriction defined as birthweight<10th percentile; 5-minute Apgar score<7; neonatal care unit admission. RESULTS: We found no effect of the COVID-19 vaccine on the rate of the individual adverse perinatal outcomes. At least one adverse perinatal outcome was found in 108 (11.25%) of unvaccinated women versus 82 (8.82%) of vaccinated pregnant women (p=0.080). Observed proportion difference (unvaccinated minus vaccinated) was 0.024; In the equivalence analysis with margin of 0.05, the 90% CI (0.01 to 0.05) lies entirely within the equivalence zone (-0.05 to 0.05) with p=0.032. CONCLUSION: Our study demonstrated an equivalent rate of adverse perinatal outcomes among vaccinated and unvaccinated women, thus supporting vaccine safety during the second and third trimesters of pregnancy. We believe this information is useful in counseling and convincing pregnant women regarding COVID-19 vaccination during pregnancy.