MRNA COVID-19 Vaccination During or Prior to Pregnancy Shows No Link to Autism or Developmental Disorders in Children

Research presented at the prestigious Society for Maternal-Fetal Medicine (SMFM) 2026 Pregnancy Meeting has delivered significant findings, confirming that receiving an mRNA COVID-19 vaccine shortly before or at any point during pregnancy is not associated with an increased risk of autism or other developmental disorders in children. This comprehensive study provides crucial new data regarding the long-term health outcomes for children whose mothers were vaccinated around the time of conception or during gestation, offering substantial reassurance to both healthcare providers and expectant parents globally. The findings, derived from a rigorous, multi-center investigation, underscore the safety profile of mRNA vaccines in this vulnerable population and aim to dispel persistent public health concerns.

Addressing Persistent Public Health Questions

The COVID-19 pandemic ushered in an unprecedented era of rapid vaccine development and widespread public health campaigns. Amidst the urgency, a significant challenge emerged in addressing public apprehension, particularly concerning novel vaccine technologies like messenger ribonucleic acid (mRNA) and their potential effects on pregnancy and child development. From the earliest days of vaccine rollout, pregnant individuals were often excluded from initial clinical trials, leading to a void in specific data and fueling understandable anxieties among expectant mothers and those planning families. This lack of initial data, combined with a pervasive landscape of misinformation and online speculation, unfortunately contributed to vaccine hesitancy within the pregnant population, despite evolving recommendations from leading health organizations.

In the United States, public health authorities, including the Centers for Disease Control and Prevention (CDC) and the American College of Obstetricians and Gynecologists (ACOG), have consistently recommended COVID-19 vaccination for all eligible individuals, including those who are pregnant, breastfeeding, or trying to become pregnant. The primary types of COVID-19 vaccines recommended have included mRNA vaccines (such as those developed by Pfizer-BioNTech and Moderna) and, subsequently, protein subunit vaccines (like Novavax). These recommendations were based on a growing body of real-world evidence demonstrating the vaccines’ efficacy in preventing severe illness, hospitalization, and death from COVID-19, as well as their favorable safety profiles in pregnant individuals, showing no increased risks of adverse pregnancy outcomes like preterm birth, stillbirth, or congenital anomalies. The benefits of vaccination—protecting both maternal health from severe COVID-19 complications and potentially conferring passive immunity to newborns—were deemed to significantly outweigh any theoretical risks. However, the specific long-term neurodevelopmental outcomes in children whose mothers were vaccinated during this critical period remained an area requiring dedicated, prospective research. This new study directly addresses that critical gap.

The Groundbreaking Maternal-Fetal Medicine Units Network Study

The investigation, a collaborative effort conducted by researchers within the esteemed Maternal-Fetal Medicine Units (MFMU) Network, represents a significant step forward in understanding the long-term impacts of maternal COVID-19 vaccination. The MFMU Network, supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), is a network of clinical centers and a data coordinating center that conducts research to improve the health of pregnant people and their children. Their expertise in conducting large-scale, rigorous studies on maternal and child health outcomes makes them uniquely suited for such an important investigation.

The study design was robust: a prospective, multi-center, and observational study that meticulously evaluated 434 children. These children, aged between 18 months and 30 months, were assessed for signs of autism spectrum disorder (ASD) and other general developmental concerns. This age range is particularly crucial as it represents a key window for early developmental screening, where signs of neurodevelopmental differences, if present, often begin to manifest and can be reliably identified using standardized tools. The study period, spanning from May 2024 to March 2025, allowed for the systematic follow-up of children born after the widespread availability of COVID-19 vaccines for pregnant individuals.

A critical aspect of the study was its comparison groups. Half of the children (217 participants) were born to mothers who had received at least one dose of an mRNA COVID-19 vaccine. This vaccination occurred either during the pregnancy itself or within 30 days prior to becoming pregnant, covering the periconceptional period, which is often a time of heightened concern regarding exposures. The remaining 217 children formed the control group, born to mothers who had not received an mRNA vaccine during or within 30 days prior to their pregnancy. This carefully constructed design allowed for a direct comparison of developmental trajectories between the two cohorts.

Expert Commentary and Reassurance

The lead researchers and affiliated experts emphasized the clear and reassuring nature of the findings. Dr. George R. Saade, MD, a senior researcher on the project and a distinguished Professor and Chair of Obstetrics and Gynecology, as well as Associate Dean for Women’s Health, at Macon & Joan Brock Virginia Health Sciences at Old Dominion University in Norfolk, VA, articulated the core conclusion: "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." This statement, coming from a highly respected figure in maternal-fetal medicine, carries substantial weight and provides a definitive answer to a question that has long troubled many. His expertise lends credibility to the meticulousness of the research and the robustness of its conclusions.

Further reinforcing the significance of the study, Dr. Brenna L. Hughes, MD, MSc, the 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, highlighted the rigorous scientific process involved. "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," Dr. Hughes stated. Her emphasis on the "rigorous scientific process" and the involvement of an "NIH clinical trials network" is crucial, as it speaks to the high standards of research design, data collection, and analysis employed, distinguishing these findings from less robust observational data or anecdotal reports. The collective endorsement from these leading experts provides a powerful message of reassurance to the medical community and the public.

Rigorous Methodological Controls for Accuracy

To ensure the highest degree of accuracy and minimize confounding variables, the researchers implemented a meticulous pairing strategy for the vaccinated and unvaccinated mothers. This involved matching participants based on several critical demographic and clinical factors:

• Delivery Location: Whether the delivery occurred in a hospital, birth center, or other setting. This helps account for potential differences in healthcare access and quality.
• Date of Delivery: Matching by delivery date helps control for temporal trends in healthcare practices, environmental exposures, or variations in the circulating viral strains.
• Insurance Status: This factor is often a proxy for socioeconomic status and access to healthcare, ensuring that groups were comparable in terms of potential resources and support systems.
• Race: Racial matching helps to account for known disparities in health outcomes and access to care, ensuring that comparisons are made between demographically similar groups.

Beyond matching, specific pregnancies were systematically excluded from both groups to further refine the study population and focus on healthy, singleton pregnancies with typical gestation. Exclusions included:

• Preterm Births: Pregnancies that ended before 37 weeks of gestation, as prematurity itself is a known risk factor for developmental challenges, independent of vaccine status.
• Multiple Gestations: Pregnancies involving twins, triplets, or more, given that multiple births also carry different developmental risks and often require specialized care.
• Major Congenital Malformations: Cases where the child was born with a major congenital anomaly, which could independently affect neurodevelopment and confound the study’s primary outcome.

These stringent exclusion and matching criteria underscore the scientific integrity of the study, enhancing confidence in the conclusion that observed outcomes were genuinely attributable to the variable of interest (maternal vaccination status) rather than other influencing factors.

Comprehensive Developmental Assessments

The evaluation of children’s development was equally thorough, utilizing a battery of well-established and validated screening tools when the children reached 1.5 to 2.5 years of age. This multi-faceted approach allowed for a comprehensive assessment across various domains of neurodevelopment:

• Ages and Stages Questionnaire Version 3 (ASQ-3): This widely used, parent-completed screening tool is designed to identify developmental delays in young children. It assesses progress in five key areas:
  • Communication: How well a child understands and uses language.
  • Gross Motor Skills: Large muscle movements like crawling, walking, and running.
  • Fine Motor Skills: Small muscle movements like grasping objects and drawing.
  • Problem Solving: Cognitive abilities related to learning and understanding.
  • Personal-Social Interaction: How a child interacts with others and develops self-help skills.
• Child Behavior Checklist (CBCL): This tool provides a comprehensive assessment of behavioral and emotional problems in children, completed by parents. It helps identify a range of issues from internalizing problems (anxiety, depression) to externalizing problems (aggression, defiance).
• Modified Checklist for Autism in Toddlers, Revised with Follow-up (M-CHAT-R/F): Specifically designed to screen for risk of autism spectrum disorder in toddlers, this questionnaire is a crucial component in early identification efforts.
• Early Childhood Behavior Questionnaire (ECBQ): This temperament questionnaire assesses various dimensions of temperament in young children, such as activity level, fear, and positive affect, providing further insight into behavioral patterns.

The combined use of these instruments provided a holistic picture of each child’s neurodevelopmental profile, allowing researchers to detect subtle differences or concerns across multiple domains, thereby strengthening the validity of the study’s conclusions. The fact that no significant differences were found across these varied and detailed assessments provides robust evidence against a link between maternal mRNA vaccination and adverse neurodevelopmental outcomes.

Implications for Public Health and Clinical Practice

The publication of these findings at a prominent medical conference like the SMFM 2026 Pregnancy Meeting, and their impending appearance in PREGNANCY, the official peer-reviewed medical journal of the Society for Maternal-Fetal Medicine, marks a critical juncture in public health messaging surrounding COVID-19 vaccination in pregnancy.

• Reinforcing Vaccine Confidence: For public health agencies like the CDC and state health departments, these results provide powerful, evidence-based data to unequivocally counter misinformation and enhance vaccine confidence among pregnant individuals and those considering pregnancy. It offers a definitive answer to one of the most persistent and emotionally charged questions regarding vaccine safety.
• Informing Clinical Counseling: Obstetricians, gynecologists, maternal-fetal medicine specialists, and primary care providers can now counsel their patients with even greater certainty. They can confidently inform expectant parents that mRNA COVID-19 vaccines do not increase the risk of autism or other developmental disorders in their children, allowing for more informed decision-making based on robust scientific evidence.
• Reducing Health Disparities: Given that vaccine hesitancy disproportionately affects certain communities, these findings could play a role in reducing health disparities by encouraging broader vaccine uptake among populations that may have been more susceptible to misinformation.
• Setting a Precedent for Future Research: The meticulous methodology employed in this study, particularly the careful matching and comprehensive developmental assessments, sets a high standard for future research investigating environmental exposures and child neurodevelopmental outcomes.

This study contributes significantly to the growing body of literature affirming the safety of COVID-19 vaccination during pregnancy. Previous studies have already established the safety of mRNA vaccines concerning other pregnancy outcomes, such as rates of miscarriage, preterm birth, and stillbirth, as well as the absence of increased risk for congenital anomalies. By adding the crucial dimension of long-term neurodevelopmental outcomes, this research provides a more complete picture of vaccine safety, reinforcing the consensus that the benefits of vaccination far outweigh any perceived risks.

Funding and Transparency

The study’s funding source, the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), an institute within the National Institutes of Health (NIH), further bolsters its credibility. The NIH is the largest biomedical research agency in the world, renowned for funding high-quality, independent scientific investigations. The authors were careful to note, however, that the conclusions presented are their own and do not necessarily reflect the official views of the National Institutes of Health, adhering to standard scientific disclosure practices. This commitment to transparency is essential for maintaining trust in scientific research.

The full details of the study, identified as Oral abstract #8, "Association between SARS-CoV-2 vaccine in pregnancy and child neurodevelopment at 18-30 months," are slated for publication in the February 2026 issue of PREGNANCY, the official peer-reviewed medical journal of the Society for Maternal-Fetal Medicine. This publication will allow the broader scientific community to scrutinize the data and methodology, further embedding these critical findings into medical literature and clinical practice guidelines. This comprehensive and reassuring study stands as a testament to the power of scientific inquiry in addressing public health challenges and providing clarity amidst uncertainty.