COVID-19 vaccination during pregnancy: a systematic review and meta-analysis

SARS-CoV-2 exposure during pregnancy is related to adverse effects for both the mother and the infant. SARS-CoV-2 vaccination has lowered the risk of symptomatic disease substantially. Recently published studies have evaluated the outcomes of women who received the COVID-19 vaccine during pregnancy; systematic evidence regarding vaccination safety is crucial to ensure that COVID-19 vaccination is not associated with adverse pregnancy and neonatal outcomes.

Pubmed/MEDLINE, EMBASE, Scopus, Web of Science, and Clinicaltrials.gov were searched from each database's inception through April 7, 2022. All interventional and observational studies comparing neonatal or pregnancy outcomes between pregnant women who received COVID-19 vaccines during their pregnancy and unvaccinated pregnant women were included. The random-effects model was used in the meta-analyses.

A total of 11 studies comprising 756,098 pregnant mothers were included. The rate of neonates with 5-min Apgar score ≤ 7 (log RR -0.08 (95% CI: -0.15 to -0.00), (P = 0.03)) and pregnant mothers with preterm birth (log RR -0.11 (95% CI: -0.21 to -0.01), (P = 0.02)) was significantly lower among vaccinated group. No significant difference was observed in adverse neonatal outcomes (log RR -0.07 (95% CI: -0.17 to 0.03)), small for gestational age (log RR -0.06 (95% CI: -0.14 to 0.02)), caesarean delivery (log RR 0.05 (95% CI: -0.05 to 0.15)), postpartum hemorrhage (log RR -0.05 (95% CI: -0.13 to 0.02)), stillbirth (log RR -0.05 (95% CI: -0.54 to 0.45)).

In this systematic review and meta-analysis, no evident differences were observed when comparing vaccinated pregnant mothers with those who had not received COVID-19 vaccines. Based on low certainty of evidence, vaccination during pregnancy was accompanied by a favorable Apgar score in neonates and fewer preterm births.