High Weight Gain in Pregnancy: Heavier, More Obesity-Prone Babies

Fat parents have fat kids. And it don't have nuthin' to do with genes.

As doctors and researchers grapple with the U.S.'s runaway rates of obesity, they have begun to look for causes of it in a critical if little understood period of life: the nine months before birth. Research has found that women who gain too much weight in pregnancy have heavier babies - and that heavier babies are more prone to obesity later on.

Until now, researchers had not been able to rule out the role of genes. If heavier mothers give birth to heavier babies, it was presumed, it could be the woman's genes that cause her to gain excessive weight during pregnancy and that those genes, passed on to her child, contribute to his or her obesity.(See pictures of pregnant-belly art.)

A new study helps eliminate that possibility. By looking at a large group of women who gave birth at least twice from 1989 to 2003, researchers were able to compare different pregnancies in the same women. Based on the data, the authors conclude that maternal weight gain during pregnancy leads to higher infant birth weight, independent of genetics. "What this study adds to the literature is the family approach, which reduces the influence of genetic factors. These kids all have the same mothers. The high birth weight isn't because of genes. It has something to do with the weight gain itself," says Matthew Gillman, director of an obesity-prevention program at Harvard Medical School. Gillman was not involved in the study.

Kudos, fatsos.