Yet another reason for women to make sure they eat right, exercise and get proper medical care while pregnant: The 3 to 8 percent slice of pregnant women in the U.S. who each year develop gestational diabetes not only have a higher risk of developing related health problems and having abnormally large infants (requiring C-sections or potentially dangerous natural deliveries) but, according to new research, also have a greater chance of birthing babies that will become obese between the ages of five and seven

The good news, according to researchers at the Kaiser Permanente Center for Health Research (CHR) in Portland, Ore., and Honolulu: treating pregnant moms with the condition that develops during, and usually ends after, pregnancy and which triggers insulin-resistance and raises blood glucose levels, could greatly reduce the chances of their tykes becoming tubby. In fact, says lead study author Teresa Hillier, an endocrinologist at CHR Northwest and Hawaii, children of stricken women successfully treated (with diet and exercise or with insulin injections) had the same risk of becoming obese as kids of women with normal blood sugar levels during pregnancy.

Hillier and colleagues analyzed the medical records of 9,439 women who gave birth between 1995 and 2000 in Portland, Ore., Washington State and Hawaii. They discovered that tots of pregnant women with untreated high blood sugar levels were 89 percent more likely to be overweight and 82 percent more likely to be obese by the ages of five to seven years (a period during which plumping up is considered a predictor of adult obesity) than were children of moms without gestational diabetes.

The bottom line, says Hillier: treat mom—and you'll also reduce her kids' chances of chunking up.

"The obesity risk of children whose mothers had the highest blood sugar levels—and were treated—was not statistically different than children of mothers with normal blood sugar levels," she says. "This suggests that you're metabolically programming your child to become obese because of being overfed in the womb … but we found that if the diabetes is treated, the risk of related childhood obesity is potentially reversible."

Hillier's advice: make sure that your ob–gyn screens for high blood sugar levels (generally between 24 and 28 weeks of pregnancy) and, if 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 and appears in next month's issue of ADA's journal, Diabetes Care. It comes on the heels of an annual report by the Trust for America's Health showing that the nation's waistline continues to expand. According to that report, obesity rates rose in 31 states and nary a one showed a dip in weight rates. Mississippi led the pack with the most obese adults, closely followed by West Virginia and Alabama.

For the first time, this year's study also took note of chubby children between the ages of 10 and 17. Washington, D.C., had the dubious honor of having the highest percentage, 22.8 percent, and Utah the lowest, weighing in at 8.5 percent.