Women who do water aerobics need less pain medicine during labor, according to a new study.

A course of water aerobics classes has been shown to reduce the amount of pain-killing medication women request during labor. as well as being safe, the gentle exercise has the benefit of making it easier to give birth.

A team from the University of Campinas in Brazil tracked 71 pregnant women. About half were randomly selected to go to three pool workout sessions a week during their pregnancies.

Lead researcher Rosa Pereira said that there was no difference in how long labor took the women or what type of delivery they had. But 27 percent of those who got in the pool asked for pain medication, compared to 65 percent in the other group.

The researchers also found that there was no harmful effect on the cardiovascular health of the women who practiced water aerobics.

"We've shown that the regular practice of moderate water aerobics during pregnancy is not detrimental to the health of the mother or the child. In fact, the reduction in analgesia requests suggests that it can get women into better psycho-physical condition," Pereira said.

The research was published in BioMed Central's open access journal Reproductive Health.