A new study suggests that pregnant women who regularly exercise during pregnancy tend to have babies with better mental performance. Researchers believe that the effects are long-term.

Researchers recommend pregnant women to take at least 20 minutes of moderate exercise on a weekly basis. They found that this activity improves the babies’ brains while inside the womb as it shows full-grown patterns of mental activity. The new study is the first to associate exercise and the mental health of the baby.

"We know exercise is good for all kinds of things in pregnancy. It makes mothers feel better, gives them more control over their weight gain, and also has an impact on their child's weight gain in life. We're saying here's an added bonus, that exercise gives your child a head-start in brain development," said Elise Labonte-LeMoyne at the University of Montreal.

The researchers led by Labonte-LeMoyne recruited pregnant women who are on their first trimester. Using randomized sampling, 10 women were asked to do moderate exercise per week such as cycling, walking, running, or swimming. The rest of the women did not exercise and maintained a sedentary lifestyle.

After the women gave birth, the researchers measured the brain activities of their babies between 8 and 12 days after birth. The assessments were conducted while the babies sleep. They played different music to make them fall asleep and observed how their brains react on different sounds. They found that those who were born by women who exercised were more reactive to the sounds.

"This is important to look at at this stage in their development, because the ability to discriminate sounds is the basis of learning to speak and to understand the sounds around you," Labonte-LeMoyne said.

The study was presented during the annual meeting of the Society of Neuroscience held in San Diego, Calif.