First-time moms-to-be who exercise have babies with normal birth weight, suggests a study published in Obstetrics and Gynecology and reported by HealthDay News.

The damage large births have on mothers and babies isn’t cute. Babies more than 8.8 pounds increase the risk of delivery problems such as cesarean sections, postpartum hemorrhage and low scores on physical evaluations for newborns. (Larger birth weights are also linked to children’s future obesity risk.)

Researchers reviewed data from the Norwegian Mother and Child Cohort study, with exercise information gathered from 37,000 women at weeks 17 and 30 of their pregnancy.

In first-time pregnant women, those who exercised at least three times a week reduced their risk of delivering a large baby by 28 percent. Those who continued exercising at 30 weeks lowered their chances by 23 percent.

“Exercise should be encouraged for everyone who’s healthy enough to do it,” said Steve Allen, chairman of obstetrics and gynecology at Scott & White Healthcare. “Exercise shouldn’t be discontinued just because you’re pregnant.”

Exercise benefits weren’t consistent for women who already had children.

Allen suggested that this might be a risk factor that is less modifiable for women who previously gave birth.

Learn more about fitness and pregnancy here.