As little as 20 minutes of moderate exercise three times per week during pregnancy enhances a newborn’s brain development, according to a small study presented today at Neuroscience 2013, in San Diego.
“While animal studies have shown similar results, this is the first randomized controlled trial in humans to measure the impact of exercise during pregnancy on the newborn’s brain,” says neuropsychologist Dave Ellemberg, of the University of Montreal. Dr. Ellemberg is the study's senior author.
“This is not to cast blame on inactive mothers,” adds study collaborator Élise Labonté-LeMoyne. “We're simply saying to pregnant women that exercise may give a slight advantage to your children's development.” Obstetricians once told women to take it easy and rest during their pregnancy, she notes.
“Today, medical societies encourage physical activity during each trimester,” comments Alycia Halladay, Autism Speaks senior director for environmental and clinical sciences. Earlier research had shown that physical activity during pregnancy reduces the risk of birth complications, eases post-partum recovery and reduces the tendency toward obesity in children. “This small study suggests that moderate exercise during pregnancy promotes brain function in the newborn as well,” says Dr. Halladay, who was not involved in the research.
Given that research has shown that exercise improves adult brain function, the Canadian researchers proposed that it might likewise benefit the developing brain during pregnancy. To verify this, they randomly assigned 18 women to either an exercise group or a sedentary group beginning in the second trimester of pregnancy. Women in the exercise group performed at least 20 minutes of cardiovascular exercise three times per week. They aimed for a moderate intensity that produced a slight shortness of breath. Women in the sedentary group didn’t exercise.
The researchers then assessed brain activity of newborns between the ages of 8 to 12 days. They did so noninvasively using electro-encephalography (EEG) caps.
“We used 124 soft electrodes placed on the infant's head and waited for the child to fall asleep on his or her mother's lap," Dr. Labonté-LeMoyne explains. “We then measured auditory memory by means of the brain’s unconscious response to repeated and novel sounds.”
The results showed that the babies born to the physically active mothers had a more-focused and mature pattern of brain activity. (See images above right.) Though less mature, the brain activity of the infants in the inactive-mom group was still within normal levels.
Next, the investigators will evaluate the children’s cognitive, motor and language development around their first birthdays, to see if the advantages persist.
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