Exercise during pregnancy can yield benefits for baby

A new study finds big benefits for mom and baby if a woman stays active during pregnancy.

A six months pregnant, Sarah Pratt Parsamian pounds the pavement with her unborn son in tow.

"I used to run 4 or 5 miles every time I'd run and now I've cut it to two because I obviously can't do that distance anymore," she said.

A new study shows that exercise during pregnancy can help Parsamian and her son.

Researchers looked at more than 36,000 women and found first-time moms who exercised three times a week in their second and third trimesters reduced their chances of delivering a baby weighing more than nine pounds by at least 23 percent.

Larger babies can be a problem for both mom and baby during delivery, Dr. Jennifer Wu said. "There are increased risks for shoulder dystocia, meaning that the head delivers, but the shoulders get stuck. This can lead to fractures and nerve damage."

Wu, of Lenox Hill Hospital, said, "When a child starts with a higher birth weight they also have increased risk of childhood obesity and adult obesity."

Parsamian's runs help her stay fit and prepare for an easier childbirth. "I already feel like I'm doing something good for my baby," she said.

The study found that exercise had the greatest benefits for first-time moms. The effects were not as significant in women who already had children.