New Study Finds COVID Vaccines During Pregnancy Don't Increase Autism Risk in Children

A new multicenter study of more than 400 mother-child pairs found no significant difference in developmental outcomes between children born to vaccinated and unvaccinated mothers, providing reassuring evidence that messenger RNA (mRNA) COVID-19 vaccines received during or shortly before pregnancy do not raise autism risk or cause other neurodevelopmental problems. The research, presented at the Society for Maternal-Fetal Medicine 2026 Annual Pregnancy Meeting, adds to decades of vaccine safety data and may help ease concerns among pregnant people considering vaccination.

What Did the Study Actually Show?

Researchers compared 217 children born to mothers who received at least one dose of an mRNA vaccine during pregnancy or within 30 days before pregnancy with 217 children whose mothers were not vaccinated during that time. The children were evaluated using several standardized screening tools designed to catch developmental delays early, including the Ages and Stages Questionnaire Version 3 (ASQ-3), the Modified Checklist for Autism in Toddlers, and the Child Behavior Checklist.

The key finding: children in both groups had essentially equivalent developmental scores. The vaccinated group showed a median difference of just 3.4 points on a 60-point scale compared to the unvaccinated group—a difference so small it falls well within the study's preset equivalence margin. There were also no significant differences in secondary measures of child behavior or developmental domains.

Why Should Pregnant People Care About This Research?

Vaccine hesitancy during pregnancy remains a real concern, and many pregnant people worry about potential risks to their developing baby. This study directly addresses one of the most persistent fears: that vaccines might harm brain development or increase autism risk. David S. Mandell, ScD, a member of the executive committee of the Coalition of Autism Scientists, emphasized the study's strengths: "There are real strengths of this study, including the clear exposed vs unexposed group and the careful assessment of children, rather than relying on a diagnosis in the electronic health record, as so many similar studies do".

Mandell further noted that "the tiny magnitude of the average difference between groups (3.4 points on a 60-point scale) increases confidence in the finding that mothers receiving the COVID vaccine during pregnancy has no effect on children's development". This careful, direct measurement of children—rather than simply checking medical records—makes the findings particularly credible.

What Do Experts Say About Vaccination Benefits During Pregnancy?

The evidence supporting prenatal COVID vaccination extends beyond just safety. According to Nancy Byatt, DO, MS, MBA, a perinatal psychiatrist and professor at University of Massachusetts Chan Medical School, "The vast majority of data that we have is consistent with COVID-19 vaccine being recommended in pregnancy and there do not appear to be major adverse risks associated with it". Byatt serves on the American Psychiatric Association Council on Women's Mental Health and brings clinical expertise to the conversation.

The rationale for vaccination becomes even stronger when considering the actual risks of COVID-19 infection during pregnancy. Research has found that female children born to mothers who had COVID in early pregnancy may have an increased chance of developing autism spectrum disorder—a finding that provides additional motivation to get vaccinated. Beyond developmental concerns, COVID-19 infection during pregnancy has been associated with:

• Severe maternal illness: Pregnant people infected with COVID-19 face higher risks of serious complications requiring hospitalization.
• Adverse pregnancy outcomes: COVID-19 infection during pregnancy increases the risk of complications affecting both mother and baby.
• Maternal death: In rare but serious cases, COVID-19 infection during pregnancy can be fatal for the pregnant person.

"The benefits of vaccination in pregnancy for COVID-19 far outweigh the risks of not being vaccinated," Byatt explained.

How Does This Fit Into the Bigger Picture of Vaccine Safety?

This new study doesn't stand alone. The Coalition of Autism Scientists released a statement noting that this research adds to the "voluminous and decades-long body of research demonstrating that vaccines are safe and do not increase risk for autism". The consistency of findings across multiple large studies—combined with the careful methodology of this particular research—provides high confidence in the safety profile.

The study was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, a federal research institute focused on maternal and child health. This independent funding source adds credibility to the findings and helps ensure the research wasn't influenced by vaccine manufacturers.

For pregnant people weighing the decision about COVID-19 vaccination, this research offers concrete reassurance: the vaccines do not harm fetal brain development, do not increase autism risk, and do not cause developmental delays. Meanwhile, the actual virus poses documented risks to both mother and baby. The choice to vaccinate during pregnancy, supported by this evidence and endorsed by major medical organizations, represents a clear path toward protecting both the pregnant person and their developing child.