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NEW YORK (Reuters Health) - Children whose mothers developed diabetes while pregnant are at increased risk of being overweight by age 11, a new study shows.
The study also found that children born to obese mothers are more likely to have a weight problem than children born to lean mothers.
"The best advice is to get lean and fit before you get pregnant," Dr. Lois Jovanovic of the Sansum Diabetes Research Institute in Santa Barbara, California, who was not involved in the study, told Reuters Health.
Earlier this week, First Lady Michelle Obama launched an action plan to combat childhood obesity. Number one in the list of recommendations was the need to stress the importance of starting a pregnancy at a healthy weight and maintaining a healthy weight throughout.
The new study, Jovanovic said, offers elegantly measured data to support this recommendation. "In order to prevent obesity in the next generation we have to do a whole lot for women in their childbearing years," she said.
Diabetes that develops during pregnancy when there is no history of the disease is called gestational diabetes. Up to 8 percent of pregnant women will develop gestational diabetes. Being overweight, when combined with the "right" genes, is an important risk factor.
Children born to mothers with gestational diabetes are often heavier at birth than children born to mothers without pregnancy-related diabetes. In the current study, Dr. Sandra Hummel and colleagues at the Technical University of Munich, Germany set out to determine the impact of mom's gestational diabetes and weight status on the child's risk of being overweight in childhood and becoming "insulin resistant" -- a precursor to full blown diabetes.
They examined data from two large German studies involving 1,420 children born between 1989 and 2000. Two hundred thirty-two children were born to mothers with gestational diabetes, 757 to mothers with Type 1, or "insulin-dependent," diabetes and 431 to non-diabetic mothers. Blood samples and body measurements were taken several times until the children were 14 years old.
The researchers found that mother's weight early in pregnancy was the strongest predictor of her child's overweight status and resulting insulin resistance.
At age 2, 8 and 11, far more children of obese mothers were overweight than children of non-obese moms, the researchers report in the journal Diabetes Care. At age 11, for example, 46 percent of children of obese moms were overweight compared with 12 percent of children of non-obese moms.
Nearly a third (31 percent) of the children born to women with gestational diabetes were overweight by age 11 compared to less than 16 percent of the children of non-diabetic moms and moms with type 1 diabetes.
The fact that a mom was diabetic only partially explained her child's tendency to be overweight. Adding obesity to the equation made a big difference leading the researchers to conclude that children born to obese women with gestational diabetes may be programed in the womb to be overweight and prone to type 2 diabetes.
The increased risk of being overweight seen in children of mothers with gestational diabetes (mainly seen in obese mothers) may be due to "a combination of genetic inheritance as well as prenatal programing," Hummel noted in an email to Reuters Health.
Because of the nature of the data, the study could not speak to the role lifestyle played in childhood obesity. More study is needed to determine that, Hummel said.
"The environment (dietary habits and physical activity shared between mothers and offspring) may be an important risk factor, which we guess is much more pronounced in later childhood/adolescence," she added.
Jovanovic said the study's findings offer a clear message to doctors.
"You don't want to tell an obese woman she can't get pregnant but if a doctor has an opportunity to help her get lean and fit before she gets pregnant -- that would be the best message from this paper," she said.
SOURCE: here 139.abstract?sid
Diabetes Care, May 2010, published online on April 30, 2010.