MIAMI (CBSMiami) – There’s good news for expectant mothers who exercise during pregnancy, it may not only improve their health but the brain development of their babies.

When Renee Rosen got pregnant her love of working out only grew, along with her belly.

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“I’ve always been pretty active. I’m pretty athletic. I do a mixture of yoga 4-5 times a week, flywheel, and strength training,” Rosen told CBS4’s Rhiannon Ally.

Rhiannon joined Renee at a prenatal yoga class at Green Monkey on Miami Beach. Many moms-to-be don’t let their pregnancy slow them down one bit.

A new study found pregnant women who performed low to medium impact workouts for at least 20 minutes a day, 3 days a week, actually help their newborns brain develop faster and could have even more positive effects as the child grows.

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“If pregnancy is the time they are going to start an exercise program and healthy lifestyle modification, what better incentive than to do it for your baby?” said Dr. Diana Friend, the Chief of Obstetrics & Gynecology at Kaiser Permanente.

Scientists placed electrode caps on babies eight to twelve days old and measured activity as their brains responded to different sounds. They say newborns with more physically active mothers had more mature brain function.

Cross-fit instructor Gio Pico continued to teach and practice the workout throughout her pregnancy. “I felt very comfortable working out and cross-fitting,” explained Pico.

Dr. Gene Burkett with the University of Miami School of Medicine said pregnant women who’ve already been doing high-intensity workouts like cross-fit should be fine, if they make some modifications.

“The injury that is likely to happen is to me, the mom, and it’s the hips, knees, so you have to be careful,” said Dr. Burkett.

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Exercising is a healthy way to keep fit during pregnancy, but Dr. Burkett advises women listen to their bodies. He recommends swimming as the best activity for pregnant women.