COVID-19 Vaccine Safety in Pregnancy, A Nested Case–Control Study in Births From April 2021 to March 2022, England

Objective: Assessment of COVID-19 vaccine safety in pregnancy using population-based data. Design: Matched case–control study nested in a retrospective cohort. Setting: April 2021–March 2022, England. Population or Sample: All pregnant individuals aged between 18 and 50 years with valid health records. Methods: Individuals identified from the national Maternity Services Data Set (MSDS) had their records linked to hospital admission, national COVID-19 vaccine and COVID-19 testing databases. Matching included participant's age and estimated week of conception. We compared outcomes across multiple COVID-19 vaccine exposures using conditional multivariable logistic regression, adjusting for demographic and health characteristics. Main Outcome Measures: Adverse pregnancy, maternal and neonatal outcomes. Results: 514 013 individuals were included. We found lower odds of giving birth to a baby who was low birthweight (aOR = 0.86, 95% CI: 0.79–0.93), preterm (aOR = 0.89, 95% CI: 0.85–0.92) or who had an Apgar score < 7 at 5 min of age (aOR = 0.89, 95% CI: 0.80–0.98) for individuals who received at least one dose of COVID-19 vaccine during pregnancy. The odds of admission to intensive care unit during pregnancy were lower in those vaccinated (aOR = 0.85, 95% CI: 0.76–0.95). There was no association between vaccination in pregnancy and stillbirth, neonatal death, perinatal death and maternal venous thromboembolism in pregnancy. Conclusions: COVID-19 vaccines are safe to use in pregnancy. Our findings generated important information to communicate to pregnant individuals and health professionals to support COVID-19 maternal vaccination programmes.