According to new research out of Columbia University, babies born to mothers who experienced a mild or asymptomatic case of COVID-19 during pregnancy had normal brain development.

The study, published on Monday in the , followed 407 infants aged from 5 to 11 months, across several regions in the U.S. between March 2021 and June 2022.

Among the infants, 258 had no documented prenatal exposure to COVID-19, 112 had confirmed exposure and 37 were exposed before pregnancy or at an indeterminate time. Just over half of the infants were born male and 367 of all infants were born to full term. The average age for the participating mothers was 32.

Researchers gave all the participating families the same children's toys and food to study the infants remotely and observe over time how their motor skills developed. The cognitive functions and language skills of the infants were also observed.

While the remote assessment was created out of necessity to provide a safe way to observe the participants during COVID, lead researcher Dani Dumitriu said evaluating the infants in their own homes made for a more natural assessment without fear of the infants feeling anxious or scared in a lab. The study authors were able to determine that babies whose mothers experienced mild or asymptomatic COVID-19 during pregnancy had a similar brain development in comparison to babies whose mothers never tested positive for COVID-19.

“The current study, which used a more rigorous method to evaluate babies born during the pandemic, provides further reassuring evidence that having a mild or asymptomatic case of COVID during pregnancy does not affect brain development in infants,†Dumitriu said in a news release. “Additional studies are needed to tell us about the impact of more severe COVID on a developing infant’s brain.â€

Research involving mothers who experienced more severe cases of COVID-19 still needs to be evaluated, as one recent study found two infants in the U.S. suffered severe brain damage after being infected with high levels of COVID-19 antibodies through their mother’s placenta. While one of the mothers did have a mild case of COVID-19, the other became extremely ill and had to deliver the baby at 32 weeks.

The Columbia University study also filled in gaps in a previous U.S. study that only focused on one region of the country. This latest study followed three different geographic regions; New York City, Salt Lake City, Utah and Birmingham, Ala. The previous study also relied on the parents' assessment of the infants while this study used a child development test conducted by university staff or students.

With files from the Associated Press.