Systematic Review: Safety and Efficacy of mRNA COVID-19 Vaccines in Pregnant Women

Abstract

Since pregnant women were excluded from clinical trials for vaccines against SARS-CoV-2, the novel coronavirus disease 2019 (COVID-19), there is limited data on the safety and efficacy of vaccines in this population. This systematic review explored the safety and efficacy of mRNA vaccines in pregnant women. A literature search was performed using Ovid databases through November 2021 for all studies evaluated efficacy and safety of mRNA COVID-19 vaccines in pregnant women. A total of five studies including 42,782 women were included in the systematic review. Humoral immunity to COVID-19 was detected in pregnant women who received the vaccine and no differences found in spike-specific T-cell responses. Incidence of high-grade chronic villitis is higher in the unvaccinated group with adjusted odds ratio of .31 (.1-.97), P < .05. Vaccination in pregnant women resulted in 12.6% spontaneous abortions (SAB) with 92.3% occurring in the first trimester, .1% stillbirth (>20 weeks gestation), 9.4% preterm birth (<37 weeks gestation), and 2.2% congenital abnormalities. The mRNA COVID-19 vaccines are immunogenic in pregnant women and no obvious safety concerns observed. There is no increased incidence of adverse reactions in pregnant women. Our finding supports that pregnant women should receive the vaccination at their earliest convenience regardless of trimester.

Keywords: COVID-19; Moderna; Pfizer-BioNTech; pregnancy; vaccination.