Add yet another reason for women to make sure they eat right and get plenty of exercise: if they don't, their children may be at greater risk for becoming obese.

Three to 8 percent of pregnant women in the U.S. each year develop gestational diabetes, a transient blood glucose condition that ends after delivery. As has long been known, those women are at higher risk for related health problems and for having abnormally large infants whose births may require either C-sections or potentially dangerous natural deliveries.

Endocrinologist Teresa Hillier and her colleagues at the Kaiser Permanente Center for Health Research (CHR) in Portland, Ore., and Honolulu analyzed the medical records of 9,439 women who gave birth between 1995 and 2000. They discovered that tots of pregnant women with untreated high blood glucose levels were 89 percent more likely to be overweight and 82 percent more likely to be obese by the age of five to seven years. (Plumping up during that period of childhood is considered one predictor of adult obesity.) “This suggests that you're metabolically programming your child to become obese because of being overfed in the womb,” Hillier says.

The good news in the CHR team's findings, however, is that controlling pregnant moms' gestational diabetes (with diet and exercise or with insulin injections) could significantly reduce the chances of their tykes becoming tubby. In fact, Hillier notes, the children of stricken women who were successfully treated had the same risk of becoming obese as the kids of women with normal blood glucose levels throughout pregnancy.

Hillier's advice to expecting mothers: make sure that your ob-gyn screens for high blood sugar levels (generally between the 24th and 28th weeks of pregnancy) and, if you are diagnosed with the condition, that you are treated and stick with the program. “It's the best thing you can do,” she says, “to reduce your child's risk of obesity.”

The study, the largest of its kind, was funded by the American Diabetes Association (ADA) and appears in the September issue of the ADA's journal, Diabetes Care.