Erica P. Gunderson, study lead author and senior research scientist in the Kaiser Permanente Division of Research in Oakland, Calif., said that their study shows that just having a history of gestational diabetes elevates a woman's risk of developing early atherosclerosis before she develops type 2 diabetes or metabolic syndrome.
Pregnancy has been under-recognized as an important time period that can signal a woman's greater risk for future heart disease and this signal is revealed by gestational diabetes, Gunderson said.
Gestational diabetes, a condition of elevated blood sugar during pregnancy, usually disappears after the pregnancy. It is managed with meal planning, activity and sometimes insulin or other medications.
In the 20-year study, researchers assessed risk factors for heart disease before pregnancy among 898 women, 18 to 30 years old, who later had one or more births. The women were periodically tested for diabetes and metabolic conditions before and after their pregnancies.
Using ultrasound, 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 measure of atherosclerosis — plaque build-up in arteries — and predicts heart attack and stroke in women. The artery's thickness was measured on average 12 years after pregnancy.
Researchers found a larger average carotid artery wall thickness in study participants with a history of gestational diabetes who did not develop diabetes or metabolic syndrome during the 20-year follow-up compared to those who never experienced gestational diabetes.
The difference was not attributed to obesity or other risk factors for heart disease that were measured before pregnancy.
It's important to recognize reproductive characteristics that may contribute to disease risk in women, Gunderson added.
The study is published in the Journal of the American Heart Association.