Large Study Finds No Link Between COVID-19 Vaccination in Pregnancy and Autism in Children

A comprehensive study of 434 toddlers found no meaningful differences in autism or developmental delays between children whose mothers received mRNA COVID-19 vaccines during pregnancy and those whose mothers did not. The research, presented at the Society for Maternal-Fetal Medicine 2026 Pregnancy Meeting, provides strong reassurance about vaccine safety for expectant mothers considering vaccination.

What Did Researchers Actually Study?

Researchers within the Maternal-Fetal Medicine Units Network conducted a prospective, multi-center study between May 2024 and March 2025. They evaluated 434 children between 18 months and 30 months of age for signs of autism and other developmental concerns. Half of the children (217) were born to mothers who received at least one dose of an mRNA COVID-19 vaccine either during pregnancy or within 30 days before becoming pregnant. The remaining 217 children were born to mothers who did not receive an mRNA vaccine during or within 30 days prior to pregnancy.

To ensure a fair comparison, researchers paired vaccinated mothers with unvaccinated mothers based on several matching factors. This careful approach helped control for other variables that might affect child development outcomes.

How Did Researchers Measure Child Development?

When the children reached between 18 and 30 months of age, researchers used multiple assessment tools to evaluate their development across several key areas. The evaluation methods included: Ages and Stages Questionnaire Version 3: This screening tool measured progress in communication, gross motor skills, fine motor skills, problem-solving, and personal social interaction. Child Behavior Checklist: Researchers reviewed this assessment to evaluate behavioral patterns and identify any concerning behaviors. Modified Checklist for Autism in Toddlers: This specialized tool specifically screens for early signs of autism spectrum disorder in young children. Early Childhood Behavior Questionnaire: This assessment provided additional insight into developmental and behavioral patterns during early childhood.

"Neurodevelopment outcomes in children born to mothers who received the COVID-19 vaccine during or shortly before pregnancy did not differ from those born to mothers who did not receive the vaccine," said George R. Saade, MD, Professor and Chair of Obstetrics and Gynecology at Old Dominion University in Norfolk, Virginia.

Why Does This Matter for Pregnant Women?

Vaccine hesitancy during pregnancy has been a significant concern, with some expectant mothers worried about potential long-term effects on their children's development. This study directly addresses one of the most common fears: the possibility of autism or developmental delays linked to mRNA COVID-19 vaccination. The findings provide evidence-based reassurance that can help pregnant women make informed decisions about their health.

Both types of COVID-19 vaccines available in the United States—the mRNA vaccine and the protein subunit vaccine—are considered safe during all stages of pregnancy and are recommended to help safeguard both maternal and infant health. Vaccination during pregnancy not only protects the pregnant person but also provides antibodies that can help protect the newborn in early infancy.

"This study, conducted through a rigorous scientific process in an NIH clinical trials network, demonstrates reassuring findings regarding the long-term health of children whose mothers received COVID-19 vaccination during pregnancy," said Brenna L. Hughes, MD, MSc, Edwin Crowell Hamblen Distinguished Professor of Reproductive Biology and Family Planning at Duke University in Raleigh, North Carolina.

The research was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and represents one of the largest prospective studies examining neurodevelopmental outcomes in children exposed to mRNA COVID-19 vaccines in utero. As more data accumulates on vaccine safety in pregnancy, expectant mothers can feel more confident in making vaccination decisions that protect their own health and their baby's wellbeing.