Children may be at greater risk of being diagnosed with autism and other neurodevelopmental disorders if their mothers were infected with Covid-19 during pregnancy, according to a new study.
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Massachusetts General Hospital researchers analyzed more than 18,000 births that occurred at Mass General Brigham Medical System between March 2020 and May 2021, checking for laboratory-confirmed Covid-19 tests among mothers and diagnoses of neurodevelopmental disorders in their children up to age 3, reports CNN.
The results showed that babies born to mothers who had Covid-19 during pregnancy were significantly more likely to receive a diagnosis of a neurodevelopmental disorder than those born to uninfected mothers: more than 16% versus less than 10%, a 1.3-fold higher risk after adjusting for other risk factors.
Overall, the differences were more pronounced for boys and when maternal infection occurred in the third trimester. The study authors note that previous research has suggested that the brain of the male fetus is more vulnerable to the mother’s immune reactions, and the third trimester represents a “critical window for brain development”.
The most common diagnoses included developmental speech and motor disorders as well as autism. About 2.7 percent of children born to mothers infected with Covid-19 during pregnancy were diagnosed with autism, compared with about 1.1 percent of others, according to the study published Thursday in the journal Obstetrics and Gynecology.
The new conclusions are “notable above all for their biological plausibility”the researchers write. They build on previous studies that have identified possible mechanisms by which maternal Covid-19 infection can affect fetal brain development even in the absence of direct transmission of the virus.
“Parental awareness of the potential risk of adverse effects on the child’s neurodevelopment after a Covid-19 infection during pregnancy is essential. By understanding these risks, parents can seek appropriate assessments and support for their children”said Dr. Lydia Shook, a maternal-fetal medicine specialist at Massachusetts General Hospital and lead author of the study.
In 2022, about 1 in 31 U.S. children will be diagnosed with autism by age 8, according to a Centers for Disease Control and Prevention (CDC) report released in April. The increase — from 1 in 36 children in 2020 — continues a long-term trend largely explained by better understanding and diagnosis of the disorder.
The time period covered by the new study — the beginning of the pandemic, before vaccines were widely available — allowed the researchers to “isolate the association between SARS-CoV-2 infection and offspring neurocognitive development in an unvaccinated population”. Approximately 93% of the mothers analyzed had not received any dose of the anti-Covid vaccine. Also, the strict infection control policies of that period reduced the possibility that some cases of Covid-19 would not have been reported or detected, the authors also explained.
“These results show that Covid-19, like many other infections during pregnancy, can pose a risk not only to the mother, but also to the developing brain of the fetus”said Dr. Andrea Edlow, a maternal-fetal medicine specialist at Mass General Brigham and lead author of the study. “They also emphasize the importance of preventing Covid-19 infection during pregnancy — a particularly relevant message at a time when public confidence in vaccines, including the anti-Covid one, is declining.”
