Even the healthiest women have a risk of developing gestational diabetes, which is characterized by high blood sugar levels, during their pregnancy. As their hormones rage, they sometimes interfere with the way insulin does its job. The Centers for Disease Control and Prevention (CDC) estimated that up to 9.2 percent of pregnant women in 2010 had gestational diabetes. If that’s not an indication of their babies’ future health, a new study finds that their children are six times more likely to develop diabetes or prediabetes.

Babies born to moms with gestational diabetes are more likely to have higher body mass indexes, putting them at a disadvantage, health-wise, from the start. When combined with an impaired glucose tolerance during their first few days of life, they become more prone to obesity and heart problems. Knowing this, researchers from the Yale University School of Medicine were interested in seeing how gestational diabetes affected children’s lives later on, particularly children who were obese but still had normal glucose tolerance (their bodies broke down sugar correctly).

“We hypothesized that prenatal exposure to GDM (gestational diabetes mellitus) in obese children with normal glucose tolerance would be associated with development of altered glucose metabolism over time, driven by an impairment in beta cell secretion relative to the insulin sensitivity,” the study authors said, according to a press release. In other words, an obese child will eventually become more resistant to insulin’s effects, causing beta cells to fall behind in insulin production, which leads to the development of type 2 diabetes.

For their study, the researchers looked at the medical histories of 225 obese teenagers who had normal glucose tolerance. They were all screened for exposure to GDM in the womb, and underwent glucose tolerance tests at the start of the study, and then three years later. Of the 18 percent of teens who were exposed to GDM, 31 percent developed an impaired glucose tolerance, which meets the criteria for prediabetes, or full-fledged diabetes.

“Our study demonstrates that that obese normal glucose-tolerant children of GDM mothers have preexisting defects in beta cell function,” the authors said, noting that it’s a strong risk factor for diabetes. “The ever-growing number of women with gestational diabetes suggests that the future will be filled with children with early diabetes at a rate that far exceeds the current prevalence.”

There are ways to prevent diabetes in all these kids, however. First and foremost, women who become pregnant should alter their lifestyles so that they’re eating better and exercising. If the child has already been born, it’s up to parents to instill healthy habits at a young age, since their child is already predisposed to a variety of health risks.

Source: Holder T, Giannini C, Santoro N, et al. A low disposition index in adolescent offspring of mothers with gestational diabetes: a risk marker for the development of impaired glucose tolerance in youth. Diabetologia. 2014.