When pregnant mothers have diabetes, their children may have altered fat cells that make metabolic diseases in adulthood more likely, a small Danish study suggests.

Babies of mothers with diabetes may be exposed to high blood sugar levels in the womb, a condition known as fetal hyperglycemia.

"Fetal hyperglycemia affects fat stem cells and these defects can be detected several years later," said lead study author Ninna Schioler Hansen of the University of Copenhagen in Denmark.

In lab tests, adult offspring of women who had diabetes during pregnancy appeared to have larger fat cells and more leptin, a protein made by fat cells that influences hunger.

"If (high blood sugar) or diabetes is present during pregnancy, our study supports the importance of aiming at normal blood glucose levels to reduce the negative impact on the cells of the unborn baby," Hansen added by email

More on this...

"Women who are lean and fit before pregnancy have a reduced risk of developing gestational diabetes during pregnancy," Hansen said.

Hansen's team studied 206 adults, including some whose mothers had diabetes before pregnancy, others whose mothers developed a condition known as gestational diabetes during pregnancy, and a control group with mothers who didn't have diabetes at all.

Adult offspring of women with diabetes in pregnancy showed "fundamental changes" in the size of their fat cells, their ability to store fat as well as the way their bodies produced the hormone leptin, which influences appetite regulation in the brain, Hansen said.

It's possible that differences between adults with and without mothers who had diabetes during pregnancy might be explained by other factors that happened during fetal development, the authors note in the Journal of Clinical Endocrinology and Metabolism.

Even so, the results offer clues to explain the increased diabetes risk among children born to mothers with diabetes, said Dr. Joachim Dudenhausen, an obstetrics and gynecology researcher at Weill Cornell Medicine in New York who wasn't involved in the study.

Changes induced by hyperglycemia in the mother "can be responsible for diabetes of the child in later life," Dudenhausen said by email.

The best prevention is for women to start pregnancy at a normal weight and gain a healthy amount of weight while they're growing their babies.

Women who start out at a normal healthy weight should gain 25 to 35 pounds during pregnancy, while women who are overweight to start should gain no more than 25 pounds, according to the U.S. Centers for Disease Control and Prevention.

"One of the highest risk factors for gestational diabetes is being overweight before and during pregnancy," Dudenhausen said.