Pregnancy pounds may affect kids' weight

Women who gain too much weight during pregnancy might raise their child's future risk of becoming overweight, a new study suggests.

Looking at data from more than 10,000 mother-child pairs, researchers at the University of Pennsylvania found that children whose mothers gained more than the recommended amount of weight during pregnancy were 48 percent more likely than other children to be overweight at age 7.

In the U.S., the Institute of Medicine (IOM) recommends that normal-weight women gain 25 to 35 pounds during pregnancy. Women who were overweight before becoming pregnant are encouraged to gain a little less - 15 to 25 pounds - while underweight women should put on 28 to 40 pounds.

The new findings suggest that exceeding those recommendations may raise a child's own odds of excessive weight gain in the future.

"Based on these results, encouraging healthy eating and aerobic physical activity for pregnant women to help meet the IOM guidelines may help curtail the childhood obesity epidemic," said lead researcher Dr. Brian Wrotniak, a postdoctoral fellow at the Children's Hospital of Philadelphia.

However, pregnancy pounds are not the whole story.

Wrotniak and his colleagues found that 7-year-olds born to women who were obese but met the IOM guidelines were still more likely to be overweight than their peers whose mothers were normal-weight but gained too much during pregnancy.

So maintaining a healthy weight before and between pregnancies should also be a goal, Wrotniak noted.

He and his colleagues report their findings in the American Journal of Clinical Nutrition.

The results are based on data from 10,266 U.S. women who gave birth between 1959 and 1965 and were part of a study looking at risk factors for cerebral palsy. As part of that project, the women gave information on their pre-pregnancy weight and had their weight measured at the time of delivery.

Their children were then followed until the age of 7.

Overall, Wrotniak's team found, a child's odds of being overweight at age 7 climbed by 3 percent for every kilogram - or roughly 2 pounds - his or her mother had gained during pregnancy.

The researchers speculate that excessive weight gain in pregnancy may affect fetal development in a way that raises the long-term risk of childhood obesity.

For example, Wrotniak explained, there is evidence that excess pounds and high blood sugar levels in expectant mothers may overstimulate fetal pancreatic cells, which produce the hormone insulin. Insulin promotes growth, and high levels can increase birthweight and, later in life, contribute to blood-sugar control problems and obesity.

However, Wrotniak stressed, even if such fetal "programming" does take place, it does not lessen the importance of children's diets and exercise levels in maintaining a healthy weight.