NEW YORK (Reuters Health) - Women who are lean and fit may have babies who are also leaner -- a fact that could affect their child's weight and health later in life, according to researchers.

In a study of mothers and their newborns, British researchers found that women who had a relatively high percentage of body fat or were self-described "slow walkers" tended to have fatter babies.

While everyone likes a chubby baby, studies have linked overly high birthweight to an increased risk of obesity later in life. Newborn body composition -- the body's relative amounts of fat and lean tissue -- likely helps to determine body composition in childhood and adulthood, study co-author Dr. Cyrus Cooper told Reuters Health.

The new findings suggest that there are things women can do to foster a healthy body composition in their children even before they're born, according to Cooper and his colleagues at the University of Southampton.

Along with not smoking, women should exercise regularly and maintain a healthy weight through a balanced diet before and during pregnancy, Cooper advised.

The study findings, published in the Journal of Clinical Endocrinology & Metabolism, are based on information gathered from 448 women before and during pregnancy. The women reported on their diet and lifestyle habits, and had their weight, height and body fat percentage measured.

Their babies' body composition was measured soon after birth.

In general, Cooper's team found, women with greater fat stores tended to have babies with a higher body fat percentage. The same was true of women who said they typically walked slowly rather than briskly.

Taller women also tended to have fatter babies, and women who'd had children before generally had chubbier newborns than first-time mothers did. While women can't change these characteristics, Cooper noted, they can do something about their body composition through good nutrition and exercise.

On the other end of the spectrum, women who are underweight or don't gain enough weight during pregnancy are at greater risk of having a low birthweight baby. In general, experts recommend that normal-weight women gain 25 to 35 pounds during pregnancy, while overweight women should gain closer to 15 to 25 pounds.