New Study Reveals: Maternal COVID-19 Infection Linked to Elevated Autism Risk in Children

In a study published Thursday that has sent ripples through the medical community, researchers at Massachusetts General Hospital have uncovered a troubling connection between COVID-19 infection during pregnancy and increased rates of autism and neurodevelopmental disorders in children. The findings, based on analysis of over 18,000 births, suggest that prenatal exposure to SARS-CoV-2 may have lasting impacts on fetal brain development. The Research: Numbers That Demand Attention The study examined 18,124 mother-child pairs from the Mass General Brigham health system between March 2020 and May 2021. Among the 861 children whose mothers tested positive for COVID-19 during pregnancy, 140—or 16.3%—received a neurodevelopmental diagnosis by age three, compared with only 9.7% of children born to mothers who did not have COVID-19 while pregnant. After adjusting for other influencing factors, the research revealed that children born to mothers who contracted COVID-19 during pregnancy face a 29% higher likelihood of developmental disorders by age three, including speech delays, motor disorders, autism spectrum disorders, and other developmental challenges. These aren't just abstract statistics—they represent thousands of children who may face lifelong challenges requiring early intervention, specialized support, and ongoing care. When Timing Matters: Third Trimester Carries Greatest Risk The research revealed that differences in risk were more pronounced among boys and in cases where the mother had a COVID-19 infection during the third trimester. This temporal pattern suggests that late pregnancy represents a particularly vulnerable window for fetal brain development. The third trimester bore the highest association with increased neurodevelopmental risks, implicating late gestation as a critical window during which viral insults may have maximal disruptive potential on the brain's structural and functional organization. Understanding this timing is crucial for both clinical surveillance and parental awareness. Women who contract COVID-19 in their final trimester may need enhanced monitoring of their children's developmental milestones in the years following birth. The Sex Disparity: Why Boys Face Higher Risk Male offspring exhibited a higher relative risk compared to females, aligning with established patterns in neurodevelopmental conditions such as autism spectrum disorder, where males are disproportionately affected. This sex-based vulnerability isn't unique to COVID-19-related outcomes. Autism spectrum disorder has long shown a male predominance, with boys diagnosed at approximately four times the rate of girls. The reasons may involve differential placental function, sex chromosome influences on immune responses, or developmental windows during brain maturation that differ between males and females. For parents of boys born during the pandemic to mothers who had COVID-19, this finding underscores the importance of vigilant developmental screening during early childhood. Understanding the Mechanisms: How COVID-19 May Affect Fetal Development Dr. Andrea Edlow, a maternal-fetal medicine specialist at Mass General Brigham and senior author of the study, explained that "COVID-19, like many other infections in pregnancy, may pose risks not only to the mother, but to fetal brain development". While viruses such as Zika or rubella have been known to cause fetal injury directly, experts believe respiratory viruses like COVID-19 are less likely to cross the placenta. Instead, researchers suspect the mechanism involves maternal immune activation—the mother's inflammatory response to infection—rather than direct viral attack on the fetus. Among toddlers with severe delays, blood tests taken at birth revealed biomarkers of activated microglia—the brain's immune cells—attacking neurons. This suggests that the maternal immune response triggers a cascade of inflammatory processes that can disrupt normal brain development in the womb. Prolonged fevers, cytokine storms, and other systemic inflammatory responses associated with COVID-19 may create an intrauterine environment hostile to optimal neural development, even without the virus directly infecting fetal tissues. The Unvaccinated Population: A Critical Research Window The timeframe of the study—early in the pandemic, before vaccines were widely available—meant that researchers were able to "isolate the association between SARS-CoV-2 infection and offspring neurodevelopment in an unvaccinated population." About 93% of the mothers included in the assessment had not received any doses of COVID-19 vaccine. This detail is scientifically significant. It allows researchers to examine the effects of COVID-19 infection itself, without the confounding variable of vaccine-induced immunity. However, it also raises an urgent question: Do COVID-19 vaccines protect against these developmental risks? Scientists said more large-scale research is needed to determine whether vaccinated mothers face the same risks or if immunity reduces the potential impact on children's neurodevelopment. Preliminary evidence suggests that vaccination may mitigate these risks by preventing severe infection and reducing inflammatory responses, but definitive answers await further research. Putting Risk in Perspective: What Parents Should Know Dr. Edlow cautioned that the findings show only an association, not proof of cause. "It's not that every pregnant woman with COVID-19 needs to think her child is going to have autism," Edlow told The Washington Post. "Overall, the absolute risk is not extremely high". Co-senior author Roy Perlis, MD, MSc, noted that "The overall risk of adverse neurodevelopmental outcomes in exposed children likely remains low". Context matters here. While a 29% increased risk sounds alarming, it's important to understand what this means in practical terms. The baseline rate of neurodevelopmental disorders is approximately 10% in the general population. A 29% increase raises that to roughly 13%—significant from a public health perspective, but still meaning that the vast majority of children born to mothers who had COVID-19 during pregnancy will develop typically. The Broader Picture: COVID-19 Joins Other Prenatal Infections Researchers say the data add to a growing body of evidence linking viral infections during pregnancy to potential neurological effects in children. This pattern isn't new—influenza, cytomegalovirus, rubella, and other maternal infections have long been associated with increased neurodevelopmental risks. What makes COVID-19 particularly significant is the sheer scale of exposure. Millions of pregnant women worldwide have contracted COVID-19 since 2020. Even if the individual risk elevation is modest, the population-level impact could be substantial. Even if small increases in risk, given the sheer number of pregnancies affected, could substantially add to the global burden of chronic disease. Clinical Implications: The Importance of Early Screening Dr. Lydia Shook, maternal-fetal medicine specialist at Massachusetts General Hospital and lead author of the study, emphasized that "Parental awareness of the potential for adverse child neurodevelopmental outcomes after COVID-19 in pregnancy is key. By understanding the risks, parents can appropriately advocate for their children to have proper evaluation and support". This statement highlights a critical point: early identification of developmental delays dramatically improves outcomes. Children who receive early intervention services for speech delays, motor difficulties, or autism spectrum behaviors show significantly better long-term trajectories than those whose challenges go unaddressed. Parents who had COVID-19 during pregnancy should: Maintain regular pediatric developmental screening appointments Be vigilant for early signs of speech, motor, or social delays Advocate for thorough evaluation if concerns arise Remember that early intervention services are most effective when started before age three The Autism Epidemic Context About 1 in 31 children in the US was diagnosed with autism by age 8 in 2022, according to a report published by the US Centers for Disease Control and Prevention in April. The increase—up from 1 in 36 children in 2020—continues a long-term trend that experts have largely attributed to better understanding of and screening for the condition. This ongoing increase in autism diagnoses predates COVID-19 and reflects multiple factors including improved diagnostic tools, increased awareness among parents and clinicians, broadened diagnostic criteria, and reduced stigma around seeking evaluation. Whether COVID-19 pregnancies contribute meaningfully to this trend remains to be seen as pandemic-era children reach school age. Vaccine Relevance in an Era of Eroding Trust The findings "support the importance of trying to prevent COVID-19 infection in pregnancy and are particularly relevant when public trust in vaccines—including the COVID-19 vaccine—is being eroded," Dr. Edlow noted. This statement acknowledges a troubling reality: vaccine hesitancy has grown even as evidence of COVID-19's potential harms accumulates. The irony is stark—as we learn more about the risks of COVID-19 infection during pregnancy, public willingness to accept protective vaccination has declined. For expectant mothers weighing vaccination decisions, this research provides crucial data: COVID-19 infection carries demonstrable risks to fetal neurodevelopment, risks that vaccination may help prevent by reducing infection severity and maternal inflammatory responses. What Comes Next: The Long View Scientists say the full consequences of in utero exposure to the coronavirus may take decades to uncover and understand. The children in this study are only three years old. Will these developmental differences persist into school age and beyond? Will additional challenges emerge as these children grow? These questions remain unanswered. Researchers continue to follow these cohorts, analyzing stored blood samples and tracking developmental outcomes over time. Understanding the long-term trajectory of pandemic-era children will require patience, ongoing research funding, and continued commitment to scientific inquiry. The Bottom Line for Expectant Parents This research doesn't mean that every child born to a mother who had COVID-19 during pregnancy will face developmental challenges. It does mean that COVID-19 infection during pregnancy is not consequence-free, and that parents should be aware, vigilant, and proactive about developmental screening. For women currently pregnant or planning pregnancy, the message is clear: preventing COVID-19 infection remains important. This includes vaccination, hand hygiene, masking in high-risk settings, and avoiding close contact with sick individuals when possible. For parents whose children were exposed to COVID-19 in utero, knowledge is power. Understanding the potential for developmental differences allows for earlier identification, faster intervention, and better outcomes. The vast majority of these children will develop typically, but for those who don't, early recognition and support can make all the difference. As we continue to understand COVID-19's long shadow, one thing becomes increasingly clear: the pandemic's impacts extend far beyond the acute illness, reaching forward into the next generation in ways we're only beginning to comprehend.