A healthy weight before and during pregnancy is good news for your child.

RODALE NEWS, EMMAUS, PA—A new study out of Germany confirms how vitally important it is to maintain a healthy weight if you’re considering having a baby. It was already known that being overweight increases risk of gestational diabetes (high blood sugar) in moms, which can lead to health problems for the newborn. This new study points to a long-term connection between gestational diabetes, the mom's body mass index (BMI) before and during pregnancy, and the weight of the child. Turns out that both gestational diabetes and overweight in the mother significantly increase the risk that her child will be overweight or obese as well, for many years down the road.

THE DETAILS: In the research, conducted by Sandar Hummel, PhD, and colleagues at the University of Munich, body weight data on children was collected at 2, 8, and 11 years after birth. By age 11, 31 percent of the children whose mothers had gestational diabetes were overweight or obese, compared to 16 percent of the children whose mothers either had type 1 diabetes or no diabetes. Maternal obesity was also a strong predictor of overweight among the children. In fact, the more overweight the mother, the greater the risk her child would turn out to be overweight or obese.

WHAT IT MEANS: Both results point to the long-lasting impact of a mother's body weight on the health of her children. “My reading of this study is that it was more about the obesity than the diabetes,” says Mary Korytkowski, MD, diabetes expert and professor of medicine at the University of Pittsburgh Medical Center. “For one thing, the children of mothers who had type 1 diabetes were no more at risk than children of mothers with no diabetes.”

And the ideal time to lower the risk is before the pregnancy. “We’ve known for some time that pre-pregnancy BMI is the strongest predictor for overweight kids,” Dr. Korytkowski adds. “And once a woman gets pregnant, we can control her gestational diabetes, but there’s only so much we can do to control her weight.” The guidelines recommend less weight gain during pregnancy if your BMI is high going in, but by then it may be too late to make a significant difference in terms of your child’s obesity risk.

“There are ways to decrease your risk of gestational diabetes—a healthy diet and active lifestyle, to name two—but the bigger point to me is the weight factor,” says Dr. Korytkowski. “You really need to get your BMI under 25 if you’re thinking about getting pregnant. Many women don’t know what their BMI is, so it’s important to get it checked so you can make lifestyle adjustments to bring it down if needed.”

Above all, Dr. Korytkowski sees these study findings as a big motivator, a call to action even. “Clearly, being overweight during pregnancy is not just about the mother, though, of course it’s important to be healthy,” she says. But knowing the obesity risk you may be passing on to your child will hopefully help motivate mothers-to-be. "As a mother, you want to do everything you can to give your child a good start, and to live a healthy life,” Dr. Korytkowski says.