Babies born into COVID-related lockdowns have taken longer to reach certain developmental milestones than babies born pre-pandemic, a study found.
Before COVID hit, parents commonly observed infants pointing at objects by 9 months old. By 1 year, many babies were saying their first words.
But the new study, published Oct. 12 by researchers at the Royal College of Surgeons in Dublin, Ireland, found that Irish infants born from March to May 2020 had a harder time communicating at 1 year old than those born between 2008 and 2011 had.
Around 89% of the infants studied who were born between 2008 and 2011 could articulate a full word like “bowl” or “cup” at 12 months old, compared to around 77% of infants born during the early months of the pandemic. The share of infants who could point at objects fell from 93% to 84%, and the portion who could wave goodbye fell from 94% to 88%.
The results were based on a questionnaire given to parents of 309 babies in Ireland during the pandemic. Around each infant’s first birthday, their parents were asked whether the baby could perform 10 different tasks, such as standing up or stacking bricks. The researchers then compared those results to a longitudinal study that assessed the same 10 skills between 2008 and 2011. Both groups of parents were asked to complete the surveys as close to their child’s birthday as possible.
For most of the time between March 2020 and April 2021, Ireland had a strict lockdown that required people to stay home except for essential activities. Residents weren’t allowed to dine inside restaurants, and people who could work at home were told to do so. Those who did not follow the rules could be fined.
Dr. Susan Byrne, the study’s author and a pediatric neurologist at the Royal College of Surgeons, said one-quarter of the babies in her study had never met another child their own age by their first birthday. When the babies were 6 months old, their families were only seeing four other people outside the home, on average, and each infant had only been kissed by three adults, including their parents.
It’s no surprise, then, that babies’ communications skills were delayed, Byrne said: “If no one’s coming to your house to leave again, you’re not going to learn how to say ‘bye, bye.’”
Byrne said some of the babies probably weren’t hearing or seeing as many people speak. Difficulty pointing, she said, could stem from the fact that babies weren’t introduced to much new stimuli beyond what was inside their house.
“Children point because either something has fallen and they want to find it, or they’re interested in a new thing and they want to see it,” Byrne said. “Obviously, if you’ve been in your lovely home the whole time, you know everything. Nothing’s new.”
The findings build on previous research that similarly suggested the pandemic hindered babies’ development. Researchers in China found that the early months of the pandemic may have delayed the development of fine motor skills, such as picking up Cheerios with a thumb and forefinger, among 1-year-olds. The findings also pointed to delayed communication skills among firstborn children who turned 1 in 2020.
In January, researchers at Columbia University found that babies born in New York City from March to December 2020 had less developed motor and social skills by six months than babies born between November 2017 and January 2020.
Those researchers hypothesized that a contributing factor might have been a mother’s emotional state while pregnant, since other studies have indicated that loneliness or stress during pregnancy could alter a child’s brain or behavioral development after they’re born. Some parents may also have had a harder time engaging with their newborns if they felt socially isolated or depressed.
“It could be a double-edged sword, where an adverse postnatal environment — so not being able to engage in the social world — is making these effects worse,” said Lauren Shuffrey, an author of that earlier study and an associate research scientist at Columbia University Medical Center.
Shuffrey said a baby’s number of social interactions probably has less effect on communication skills within their first year than the quality of those interactions.
“Having someone who is socially engaged with that infant, whether that be one person or two people — that is the most important thing,” she said.
Neither Byrne nor Shuffrey expect these delays to be permanent.
“I don’t think that these small differences really early on in development mean that these kids are on a life course of having developmental delays,” Shuffrey said. “These are really small differences and we know that infants’ and young children’s brains are super malleable.”
Shuffrey said her own daughter was born during the pandemic and has transitioned from social isolation to attending nursery school and going on playdates. Those new experiences will shape her daughter’s social development, she said, even if there’s catching up to do.
Contrary to the other observed trends, the researchers in Ireland found that 97% of pandemic babies were able to crawl at 1 year compared to 91% of babies born earlier. Byrne said that’s probably because babies spent more time at home during lockdown and less time in strollers or carseats.
Her team will continue to observe the same babies to see how their communication skills change by age 2, or perhaps even older.
“I think the two-year data is going to be really informative,” Byrne said. “At 2, you’re better able to look at all of the developmental milestones. You can get a better assessment of what children are able to do because they can do more things.”
This story first appeared on NBCNews.com.