Covid-19 third vaccination during pregnancy: maternal and neonatal outcomes—a retrospective study

Purpose: To evaluate the impact of Covid-19 (Pfizer-BioNTech BNT162b2) third booster dose vaccination during pregnancy on maternal and neonatal outcomes. Methods: This is a multicenter, retrospective computerized database study. Parturients who delivered in Israel between August and December 2021 with full records of Covid-19 disease and vaccination status were included. Those who received third booster during pregnancy were compared to those who received two doses of vaccine during pregnancy and to unvaccinated parturients. Various adverse maternal and neonatal outcomes were evaluated. Parturients who were previously positive with Covid-19 PCR swabs during pregnancy or before pregnancy were excluded. Univariate analysis was followed by multivariate analysis. Results: A total of 2583 women were included in the analysis; 626 received the third booster dose of the BNT162b2 Covid-19 vaccine, 1094 received two doses of the vaccine, and 863 unvaccinated women. Maternal and neonatal outcomes were comparable between the study groups. An adjusted multivariable logistic regression analysis demonstrated that receiving the third booster was not associated with an increase in neither composite adverse maternal or neonatal outcome (aOR 0.9; 95% CI [0.65–1.22], p = 0.47; aOR 0.7; 95% CI [0.53–1.035], p= 0.09, respectively) when compared to those who received two doses of the vaccine. However, administration of the third booster dose during pregnancy was associated with a reduced composite adverse neonatal outcome when compared to unvaccinated women (aOR 0.6; 95% CI [0.42–0.86], p = 0.01). Conclusion: Receiving the third booster dose of the BNT162b2 Covid-19 vaccine during pregnancy is not associated with an increased risk of any adverse maternal outcomes and may be beneficial for the neonates.