Large study finds no link between mRNA COVID vaccine in pregnancy and autism

The groundbreaking findings, unveiled at the prestigious Society for Maternal-Fetal Medicine (SMFM) 2026 Pregnancy Meeting, provide robust new evidence to alleviate long-standing concerns regarding the safety of mRNA COVID-19 vaccines in the peripregnancy period. This comprehensive study, which meticulously tracked the neurodevelopmental outcomes of hundreds of toddlers, definitively concludes that vaccination around the time of conception or at any point during gestation does not increase the risk of autism spectrum disorder or other developmental delays in offspring. The research marks a crucial milestone in understanding the long-term health implications for children whose mothers received these vital immunizations, reinforcing the established safety profiles and public health recommendations.

The Study’s Crucial Findings and Methodology

Conducted by researchers within the esteemed Maternal-Fetal Medicine Units Network, the investigation observed 434 children, aged between 18 months and 30 months, specifically looking for indicators of autism and other developmental concerns. The study’s design was prospective, multi-center, and observational, unfolding between May 2024 and March 2025. This rigorous methodology allowed researchers to collect real-time data, enhancing the reliability and applicability of their conclusions.

The cohort was evenly split: 217 children were born to mothers who had received at least one dose of an mRNA COVID-19 vaccine either during their pregnancy or within 30 days prior to becoming pregnant. The remaining 217 children served as the control group, born to mothers who did not receive an mRNA vaccine during the comparable peripregnancy window.

"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," affirmed senior researcher George R. Saade, MD. Dr. Saade, who is Professor and Chair of Obstetrics and Gynecology and Associate Dean for Women’s Health at Macon & Joan Brock Virginia Health Sciences at Old Dominion University in Norfolk, VA, underscored the study’s clear and reassuring results, which directly address a significant area of public concern.

To ensure the highest level of accuracy and minimize confounding variables, the research team employed a meticulous matching process. Vaccinated mothers were carefully paired with unvaccinated mothers based on several critical factors: their place of delivery (e.g., hospital, birth center), the exact date of delivery, insurance status, and race. Furthermore, specific pregnancies were excluded from both groups to maintain homogeneity and focus on typical developmental trajectories. These exclusions included pregnancies that concluded before 37 weeks, those involving multiple babies (e.g., twins or triplets), or those that resulted in a child with a major congenital malformation. This stringent control over variables strengthens the causal inference of the study.

When the children reached the age range of 1.5 to 2.5 years, their development was comprehensively assessed using a suite of validated screening tools. The primary instrument was the Ages and Stages Questionnaire Version 3 (ASQ-3), a widely recognized and respected screening tool that measures progress across five crucial developmental domains: communication, gross motor skills, fine motor skills, problem-solving abilities, and personal-social interaction. To further corroborate and enrich the developmental profile, the research team also reviewed results from the Child Behavior Checklist (CBCL), the Modified Checklist for Autism in Toddlers (M-CHAT), and the Early Childhood Behavior Questionnaire (ECBQ). The combined use of these instruments provided a holistic and nuanced evaluation of each child’s behavioral and developmental patterns.

Brenna L. Hughes, MD, MSc, Edwin Crowell Hamblen Distinguished Professor of Reproductive Biology and Family Planning and Interim Chair of the Department of Obstetrics and Gynecology at Duke University in Raleigh, NC, praised the study’s robust nature. "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," she stated, highlighting the credibility conferred by its affiliation with the National Institutes of Health.

Addressing Persistent Concerns: The Autism Link

The specific focus of this study on autism and other neurodevelopmental disorders is particularly significant given the historical landscape of vaccine hesitancy. For decades, a persistent, albeit thoroughly debunked, myth linking vaccines to autism has plagued public health efforts, stemming largely from a fraudulent 1998 study regarding the MMR vaccine. This misinformation has created a fertile ground for skepticism, which resurfaced with the rapid development and deployment of novel COVID-19 vaccines.

Despite overwhelming scientific consensus on vaccine safety, the introduction of new mRNA technology, combined with the unprecedented speed of vaccine development during the pandemic, fueled renewed anxieties among some segments of the population, particularly expectant parents. Concerns about potential long-term effects on fetal development and childhood neurodevelopment were frequently raised, often amplified by online misinformation campaigns. This SMFM 2026 study directly confronts these specific anxieties, providing evidence-based answers that can help dismantle lingering doubts. By demonstrating no association between mRNA COVID-19 vaccination and adverse neurodevelopmental outcomes, the research offers a powerful counter-narrative to persistent misinformation.

The Role of mRNA Vaccines in Pregnancy: A Timeline of Guidance

The COVID-19 pandemic, which swept across the globe starting in early 2020, necessitated an urgent scientific response. The development of mRNA vaccines, specifically those from Pfizer-BioNTech and Moderna, represented a monumental leap in vaccine technology. Unlike traditional vaccines that use weakened or inactive forms of a virus, mRNA vaccines teach human cells how to make a harmless piece of the virus’s spike protein, triggering an immune response without ever introducing the live virus into the body. Critically, these vaccines do not interact with or alter human DNA.

• December 2020: The U.S. Food and Drug Administration (FDA) grants Emergency Use Authorization (EUA) for the first mRNA COVID-19 vaccines for adults. Initial guidance for pregnant individuals was cautious due to limited data.
• Early 2021: As real-world data emerged, major medical organizations like the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) began to issue statements, initially suggesting that pregnant individuals could choose to be vaccinated after discussion with their healthcare providers, recognizing the theoretical benefits often outweighed the theoretical risks.
• August 2021: Following accumulating safety data from millions of vaccinated pregnant individuals and the increasing understanding of the severe risks of COVID-19 infection during pregnancy, the Centers for Disease Control and Prevention (CDC) strongly recommended COVID-19 vaccination for all people 12 years and older, including those who are pregnant, breastfeeding, or trying to become pregnant. This recommendation was swiftly endorsed by ACOG and SMFM.
• Throughout 2022-2023: Booster doses and updated formulations were recommended, with guidance consistently affirming safety and efficacy for pregnant populations.
• May 2024 – March 2025: The "Association between SARS-CoV-2 vaccine in pregnancy and child neurodevelopment at 18-30 months" study, the subject of this article, was conducted.
• February 2026: The study’s findings are presented at the SMFM 2026 Pregnancy Meeting and slated for publication.

Throughout this timeline, the scientific consensus solidified: COVID-19 infection during pregnancy poses significant risks, including an increased likelihood of severe illness, ICU admission, mechanical ventilation, and even death for the mother. Pregnant individuals with COVID-19 also face elevated risks of adverse pregnancy outcomes such as preterm birth, preeclampsia, and stillbirth. Conversely, studies consistently demonstrated that mRNA COVID-19 vaccines are safe and effective during all stages of pregnancy, conferring protection to both the mother and, through passive immunity, to the newborn. The U.S. also recommends a protein subunit vaccine, though the current study focused specifically on the widely adopted mRNA platforms.

Broader Implications for Public Health and Trust

The publication of these findings holds profound implications for public health, medical practice, and the ongoing battle against misinformation.
Firstly, it provides definitive, long-term reassurance to millions of parents who received an mRNA COVID-19 vaccine during or around their pregnancy. For those who made the decision to vaccinate based on initial guidance, this study validates their choice and offers peace of mind regarding their children’s neurodevelopmental health. For those who were hesitant, this robust evidence may help alleviate anxieties and encourage future vaccine uptake, including for other recommended immunizations.

Secondly, the study empowers healthcare providers, particularly obstetricians, maternal-fetal medicine specialists, and pediatricians, with an additional layer of evidence to counsel their patients. Having concrete data from a prospective, multi-center study on long-term neurodevelopmental outcomes will strengthen their recommendations and help address patient concerns with greater confidence. Public health organizations, including the CDC, ACOG, and the American Academy of Pediatrics, are expected to widely publicize these findings to reinforce their existing guidance and promote vaccine confidence.

Thirdly, this research represents a critical victory in the fight against vaccine misinformation. By directly investigating and disproving a commonly propagated false claim about vaccines and neurodevelopment, it underscores the importance of rigorous scientific inquiry in shaping public health policy. It demonstrates how the scientific community proactively addresses public concerns with data, contrasting sharply with the speculative and often fear-mongering narratives perpetuated by anti-vaccine proponents. This systematic approach to evidence generation is vital for maintaining public trust in scientific institutions and medical advice.

Looking Ahead: Future Research and Continued Surveillance

While this study offers substantial reassurance, the scientific journey is ongoing. Future research may explore even longer-term developmental outcomes, evaluate potential effects on other health parameters in children, or delve deeper into specific subgroups. Continued surveillance of vaccinated populations remains a cornerstone of pharmacovigilance and public health monitoring, ensuring that the safety and efficacy of all medical interventions are continuously assessed.

The study was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), a testament to its public health importance. The authors noted that the conclusions presented are their own and do not necessarily reflect the official views of the National Institutes of Health. The oral abstract #8, "Association between SARS-CoV-2 vaccine in pregnancy and child neurodevelopment at 18-30 months," is scheduled for publication in the February 2026 issue of PREGNANCY, the official peer-reviewed medical journal of the Society for Maternal-Fetal Medicine, making this vital information accessible to the broader medical and scientific communities. This comprehensive publication will allow for detailed review and further dissemination of these crucial findings, solidifying their place in evidence-based maternal and child healthcare.