New Study Finds Higher Autism and Neurodevelopmental Diagnosis Rates in Children Whose Mothers Had COVID-19 During Pregnancy

A large new study links maternal COVID-19 during pregnancy with a modestly higher risk of autism and other neurodevelopmental disorders by age three. Learn what the research found, possible explanations, limitations, and practical guidance for parents and clinicians. (Lippincott Journals)

Introduction

A growing body of research published since the start of the pandemic is beginning to examine an important — and understandably alarming — question: does a SARS-CoV-2 infection during pregnancy increase the chance that a child will receive an autism or other neurodevelopmental diagnosis? A large, recent cohort study from Mass General Brigham and colleagues adds to earlier reports by finding that children born to mothers who tested positive for COVID-19 while pregnant were more likely to have a neurodevelopmental diagnosis by age three than children whose mothers were not infected. (Lippincott Journals)

What the new study actually found

Researchers analyzed electronic health records for 18,124 live births at Mass General Brigham from March 2020 through May 2021. Among the 861 children whose mothers had documented SARS-CoV-2 infection in pregnancy, 16.3% had a neurodevelopmental diagnosis by age three, compared with 9.7% of the children whose mothers were not infected. After adjusting for several factors (including maternal age, race, insurance status, preterm birth and other potential confounders), maternal infection was associated with an approximately 29% higher likelihood of a neurodevelopmental diagnosis in the child by age three. The effect appeared strongest for infections occurring in the third trimester and was more pronounced in male offspring. (Lippincott Journals)

What "higher risk" means in practical terms

A 29% relative increase can sound large, but it’s important to put that into absolute perspective. If 10 out of every 100 children in one group receive a diagnosis, a 29% relative increase would raise that to about 13 out of 100 — an increase of three additional diagnoses per 100 children. In other words, while the relative risk rises, the absolute risk for any individual child remains relatively low. Multiple outlets reporting the finding emphasize that most children born to infected mothers do not receive neurodevelopmental diagnoses. (News-Medical)

Possible reasons behind the association

Experts point to several biologically plausible explanations — none of which prove causation on their own:

• Maternal immune activation (MIA): Viral infections in pregnancy can trigger inflammatory responses (cytokine release) that cross the placenta or affect placental function, potentially influencing fetal brain development. This is a well-studied pathway in animal models and human epidemiology of other infections. (Nature)
• Timing matters: The study’s stronger signal for third-trimester infections hints that timing of exposure could affect which brain processes are disrupted.
• Indirect factors: Severe maternal illness (fever, hypoxia), medications, elevated stress, disruptions to prenatal care, or preterm birth could all contribute to developmental risk. The new study adjusted for some, but not all, of these factors. (Lippincott Journals)

What the research does not show

Crucially, observational studies cannot by themselves prove that maternal COVID-19 causes autism. The new analysis controls for several confounders, but residual confounding (unmeasured factors that differ between infected and uninfected mothers) is possible. Also, the study identifies diagnoses by age three — some developmental issues are diagnosed later, and early screening can both under- and over-capture concerns. Earlier pandemic research produced mixed findings, with several studies finding no strong links and others suggesting modest associations, so the picture remains nuanced. (JAMA Network)

How clinicians and parents should interpret this

• Awareness, not panic. The finding justifies careful developmental monitoring for children known to have been exposed in utero, but it does not mean most exposed children will develop autism or other disorders.
• Early screening helps. Pediatricians and parents should follow standard well-child screening schedules and consider early referral for evaluation if concerns arise. Early intervention services are among the most effective tools for improving long-term outcomes. (cidrap.umn.edu)
• Pregnancy prevention remains important. The study adds a reason to encourage COVID-19 prevention strategies during pregnancy — vaccination, masking in high-risk situations, and seeking prompt care for symptomatic disease — not only to protect maternal health but potentially to reduce risks to the fetus. Public health bodies have consistently recommended vaccination for pregnant people because it reduces severe maternal illness. (massgeneralbrigham.org)

Limitations researchers acknowledge

The authors and independent experts emphasize that the findings are preliminary and require replication in other large, diverse cohorts with longer follow-up. Key limitations include reliance on electronic health record diagnoses (which can vary by access to care), a study period concentrated during early pandemic waves (before widespread vaccination), and limited granularity on severity of maternal illness, vaccination status, and socioenvironmental factors. Longer-term follow-up will clarify whether early diagnoses persist or whether patterns change as children age. (Lippincott Journals)

What’s next for research

Researchers are already calling for multi-site studies that incorporate biological samples (placenta, cord blood), detailed timing and severity data, and genetic or familial risk measures to untangle mechanisms. Understanding whether the association reflects a specific effect of SARS-CoV-2 or the broader consequences of maternal immune activation will shape both prevention and treatment strategies. (Nature)

5 FAQs

Q1: Does maternal COVID-19 definitely cause autism?
A1: No. Current studies show an association in some cohorts, but observational data cannot prove causation. More research is needed to confirm findings and explain mechanisms. (Lippincott Journals)

Q2: Which trimester is most risky?
A2: The new study found stronger associations for infections in the third trimester, but other research suggests different windows may matter for different outcomes; timing is an important factor to study further. (Lippincott Journals)

Q3: Should pregnant people get vaccinated to reduce risk?
A3: Public health agencies recommend COVID-19 vaccination during pregnancy to protect both maternal and fetal health. Vaccination reduces the risk of severe maternal illness, which may reduce downstream risks to the fetus. (massgeneralbrigham.org)

Q4: How common are neurodevelopmental diagnoses after prenatal COVID exposure?
A4: In the Mass General Brigham cohort, about 16% of exposed children had a neurodevelopmental diagnosis by age three compared with 9.7% of unexposed children — a relative increase but a modest absolute difference. (Lippincott Journals)

Q5: What should parents do if their child was exposed in utero?
A5: Follow routine pediatric care and developmental screening. If you notice delays in speech, motor skills, social engagement, or other concerns, discuss them promptly with your pediatrician to access early evaluation and services.

Conclusion

The latest, large observational study adds weight to concerns that maternal SARS-CoV-2 infection in pregnancy may modestly elevate the risk of autism and other neurodevelopmental diagnoses by early childhood — particularly following third-trimester exposure and in boys. However, the research is not definitive and cannot establish cause and effect. For parents and clinicians, the practical message is clear: stay informed, emphasize prevention in pregnancy (including vaccination), and prioritize early developmental screening and intervention when concerns emerge. Continued research — including longer follow-up, biological sampling, and replication in diverse populations — will be crucial to translate these early findings into clear clinical guidance.