Exercising Moms-to-Be May Have Less-Chubby Babies
This could benefit newborns later in life, researcher suggests
But he said these latest findings add to evidence that exercise benefits mothers-to-be and their babies.
The study included 826 Colorado women, average age 28, whose activity levels were tracked during pregnancy. Only 17 percent met the recommended guidelines on exercise. About 45 percent were overweight or obese.
In general, the researchers found, the one-quarter of women who were most active in late pregnancy tended to have less chubby babies than other mothers. Those active women were not running marathons -- most got a modest amount of exercise on most days of the week, Dabelea said.
The researchers did find that the most-active mothers had an increased risk of having a "small-for-gestational-age" newborn -- which means smaller than the norm for babies born during a given week of pregnancy.
But Dabelea attributed that to the lower level of body fat, rather than impaired growth and development in the womb.
Another ob/gyn who reviewed the study said the higher likelihood of small-for-gestational-age newborns is "a little concerning." But there's no way of knowing whether there could be negative effects in the long run.
"Is there a benefit from the lower fat mass? We don't know yet. Is there a risk from being [small-for-gestational-age] when there is no effect on lean body mass? We don't know," said Dr. Jill Rabin, co-chief of ambulatory care and women's health programs at North Shore-LIJ Health System, in New Hyde Park, N.Y.
Dabelea agreed that longer-term research is needed to see whether that lower fat mass at birth actually benefits children's health.
But what is clear, the experts said, is that a generally healthy lifestyle is vital during pregnancy and before.
"It's important to start optimizing your health before you become pregnant," Rabin said. "Eat a healthy diet, get regular exercise, take prenatal vitamins, quit smoking."
But even if a woman was sedentary before, it's safe to start exercising during pregnancy, Fernandez said. Women can ask their doctors about the types of exercise that are appropriate, he said. In general, activities such as walking, swimming and cycling are suggested.