Doctors measured babies' brain activity for a study on exercise in pregnancy. (Credit: Courtesy University of Montreal )

By Shazia Mehmood Siddique, M.D.

For women who are pregnant, as little as 20 minutes of exercise three times per week can advance a newborn's brain activity, according to a new study.

Researchers at the University of Montreal presented these findings at the Neuroscience 2013 conference in San Diego on Sunday, providing moms-to-be with even more reasons to make exercise a priority.

In their study, the researchers randomly assigned 60 women to two groups: women who were provided with an exercise regimen, and those who were not. The women kept daily logs of exercise, and pedometers and accelerometers allowed researchers to keep track of the women's level of activity. Once the babies were born, the researchers recorded their brain activity levels at 8 to 12 days of life. They found that the babies of mothers who exercised had brains that were more fully developed.

Current recommendations by the American College of Obstetrics and Gynecologists urge moderate exercise, about 30 minutes almost daily, during pregnancy. The guidelines are based on findings that moderate exercise can improve back aches, prevent pregnancy-associated diabetes and improve sleep.

This paper is the first of its kind to study the impact of exercise on the newborn, said study researcher Élise Labonté-LeMoyne of the University of Montreal.

"We measured directly the brain activity," Labonté-LeMoyne said. "So it's not a behavioral test or neuropsychologic test, it's really specifically the brain that we were looking at." She added that the measurement of electrical brain activity is "the most indicative way to measure a newborn's cognitive status."

Women's health experts not involved with the research said it provides yet another important reason for pregnant women to stay active.

"We know that aerobic exercise has an immediate result of increasing mitochondrial activity in the brain, but this study shows that this effect may in fact 'cross the placenta' and benefit the fetal brain as well," said ABC News senior medical contributor Dr. Jennifer Ashton, who is also a board-certified obstetrician and gynecologist. "More studies with larger numbers are needed and we also need to follow these fetuses through early life to see if these effects result in higher aptitude or accelerated development down the road."

"This is yet another study showing the importance of staying active in pregnancy," said ABC News medical contributor Dr. Jacques Moritz, a board-certified ObGyn at St. Luke's-Roosevelt Hospital in New York. "And now another reason to exercise would be possibly to even make your baby smarter."

Doctor's Take:

In decades past, the conventional wisdom has been that resting during pregnancy was important for the baby's safety. This, unfortunately, is a misconception that is occasionally still seen today. Now, however, we know that regular exercise can be beneficial to women's health in various ways - including improvements in mood and energy during pregnancy. With this new study, there is even stronger incentive to exercise for your baby's health, too.

Before engaging in strenuous physical activity during pregnancy, or if you have a complicated pregnancy, talk to your doctor first. But setting daily goals for 30 minutes of exercise is an important and great start to your pregnancy and to your baby's life.