Is SARS-CoV-2 vaccination during pregnancy associated with adverse pregnancy outcomes? In this population-based retrospective cohort study that included 157 521 deliveries in Sweden and Norway, SARS-CoV-2 vaccination during pregnancy, compared with no SARS-CoV-2 vaccination during pregnancy, was not significantly associated with risk of preterm birth (adjusted hazard ratio [aHR], 0.98), stillbirth (aHR, 0.86), small for gestational age (adjusted odds ratio [aOR], 0.97), low Apgar score (aOR, 0.97), or neonatal care admission (aOR, 0.97).

Pregnant women with COVID-19 are at increased risk for severe illness and adverse birth outcomes, yet many remain reluctant to be vaccinated. In a retrospective cohort of >40,000 pregnant women, COVID-19 vaccination during pregnancy was not associated with preterm birth or small-for-gestational-age at birth overall, stratified by trimester of vaccination, or number of vaccine doses received during pregnancy, compared with unvaccinated pregnant women.

Among 3958 participants enrolled in the v-safe pregnancy registry, 827 had a completed pregnancy, of which 115 (13.9%) resulted in a pregnancy loss and 712 (86.1%) resulted in a live birth (mostly among participants with vaccination in the third trimester). Adverse neonatal outcomes included preterm birth (in 9.4%) and small size for gestational age (in 3.2%); no neonatal deaths were reported.