Women who develop gestational diabetes may face an increased risk of early heart disease later in life, even if they do not develop diabetes subsequent to their pregnancy, U.S. researchers said Wednesday.

Gestational diabetes, a condition of elevated blood sugar during pregnancy, usually disappears after the pregnancy.

Researchers from the Kaiser Permanente measured risk factors for heart disease before pregnancy among 898 women, 18 to 30 years old, who later had one or more births and were followed for 20 years. Overall, 119 women, or 13 percent, reported they had developed gestational diabetes.

Using ultrasound, the researchers measured the thickness of the walls of participants' carotid artery, which circulates blood to the neck and face. Carotid artery wall thickness is an early sign of heart attack in women. The artery's thickness was measured on average 12 years after pregnancy.

Among the women who did not develop diabetes or the metabolic syndrome during the 20-year follow-up, those who had gestational diabetes had a larger average carotid artery wall thickness than those who didn't have gestational diabetes.

The difference was not attributed to obesity or other risk factors for heart disease that were measured before pregnancy.

"This finding indicates that a history of gestational diabetes may influence development of early atherosclerosis before the onset of diabetes and metabolic diseases that previously have been linked to heart disease," lead author Erica Gunderson, a senior research scientist with Kaiser Permanente's Division of Research in Oakland, California, said in a statement.

"Gestational diabetes may be an early risk factor for heart disease in women," Gunderson said.

The results were published in the Journal of the American Heart Association.