(Reuters Health) - Pregnant women who use cell phones may be no more likely to have kids with brain development problems than expectant mothers who avoid mobile devices, a recent study suggests.

“We found no evidence of a harmful effect of the mother using her cell phone during pregnancy on her child’s neurodevelopment at 3 and 5 years,” said senior study author Dr. Jan Alexander of the Norwegian Institute of Public Health.

“To our surprise, the more the mother was using her cell phone during pregnancy, the better language and motor skills her child had at 3 years of age,” Alexander said by email. “A similar finding for father’s use, however, points to other lifestyle factors and not the physical impact of cell phones.”

Some previous research, primarily in animals, has raised concerns about whether exposure to radiofrequency electromagnetic fields from cell phones might harm developing babies’ brains. But results have been mixed, and many of the studies have been too small or brief to assess the long-term impact of cell phone exposure on child development, researchers note in BMC Public Health.

For the current study, researchers examined data on 45,389 mother-child pairs, surveying women about their cell phone use during pregnancy and their child’s language, communication and motor skills at age 3 and 5.

Overall, about 10 percent of the women said they never or rarely used cell phones while they were pregnant, while 39 percent were considered “low” users, 47 percent were “medium” users and about 4 percent were “high” users.

Researchers considered women low users if they were on cell phones a few times a week and medium users if they were on mobile devices daily. The high users were on cell phones at least an hour every day.

Compared to kids born to women who rarely if ever used cell phones during pregnancy, children of cell phone users had a 27 percent lower risk of having low sentence complexity, 14 percent lower risk of incomplete grammar and 31 percent lower risk of having moderate language delay at age 3, the study found.

Children born to mobile phone users also had an 18 percent lower risk of low motor skills at age 3.

The study isn’t a controlled experiment designed to prove whether or how cell phone exposure during pregnancy might influence child development. Parents also might have provided inaccurate information on their child’s language development.

Even so, the findings should reassure expectant mothers that using a cell phone won’t necessarily harm babies’ developing brains, the researchers conclude.

But other research has linked cell phone exposure to developmental problems like hyperactivity, and one study isn’t enough to settle questions about the safety of exposing babies to mobile phones in utero, said Laura Birks, a researcher at the Barcelona Institute for Global Health (ISGlobal) who wasn’t involved in the study.

“I would not say that women have no reason to worry about cell phone use during pregnancy,” Birks said by email.

“While this study demonstrates a correlation between high cell phone use and improved language and motor skills in the child, we cannot conclude that this relationship is causal or that the child is not experiencing some other adverse effect of radio frequency exposure,” Birks added.

“If pregnant women want to reduce radiofrequency exposure while taking on the phones, they can use the hands-free function while talking on the phone and avoid holding the phone next to the abdomen,” Birks advised.

SOURCE: bit.ly/2yG9dUy BMC Public Health, online September 5, 2017.