Sign in Subscribe
Coronaviruses

mRNA COVID-19 Vaccines Safe in Early Pregnancy, Says New Study

Strategic Insights

— 1 min read

A new study on the safety of messenger RNA (mRNA) COVID-19 vaccines during the first trimester of pregnancy has found no association with an increased risk of major congenital malformations (MCMs). The nationwide, population-based cohort study in France included over 527,000 live-born infants and found that mothers who received at least one dose of mRNA-based COVID-19 vaccine during the first trimester had a slightly older age, were less socially deprived, and presented with slightly more comorbidities compared to those who were not vaccinated.

Key Takeaways:

  • The study, conducted using the comprehensive Mother-Child EPI-MERES Register, analyzed data from over 527,000 live-born infants in France from pregnancies starting April 1, 2021, to January 31, 2022.
  • Exposure to mRNA-based COVID-19 vaccine during the first trimester was defined as receiving at least one dose of the vaccine during the first trimester of pregnancy.
  • The prevalence of MCMs was 176.6 per 10,000 among exposed infants and 179.4 per 10,000 among non-exposed infants.
  • No increased risk of MCMs was observed overall, by organ system, or for any of the 75 individual MCMs.
  • Sensitivity and stratified analyses confirmed these findings, supporting the safety of mRNA COVID-19 vaccines in early pregnancy.
  • The study's results were published in the JAMA Network Open journal on October 28, 2025 (JAMA Network Open, 2025;8(10)).

Statistics:

  • 527,564 eligible live-born infants were included in the study.
  • 130,338 (24.7%) were exposed to at least one vaccine dose during the first trimester.
  • The weighted odds ratios (ORs) were estimated using logistic regression and found no increased risk of MCMs overall (weighted OR, 0.98 [95% CI, 0.93-1.04]).
  • The prevalence of MCMs among exposed infants was 176.6 per 10,000, and 179.4 per 10,000 among non-exposed infants.

Sources:

  • First-Trimester mRNA COVID-19 Vaccination and Risk of Major Congenital Anomalies (JAMA Network Open, 2025;8(10)).
  • Tom Duchemin, EPI-PHARE Scientific Interest Group in Epidemiology of Health Products, French National Agency for Medicines and Health Products Safety (ANSM) and French National Health Insurance (CNAM), Saint-Denis, France.
  • Amer Medical Assoc, 330 N Wabash Ave, Ste 39300, Chicago, IL 60611-5885, USA.

Read more