Expecting mothers, take note.
A new study indicates that diabetes during pregnancy may increase the risk of heart disease.
The study suggests that women with a history of diabetes during pregnancy (gestational diabetes) are twice as likely by mid-life to develop calcium in heart arteries - a strong predictor of heart disease - even if healthy blood sugar levels were attained many years after pregnancy.
"We were surprised to discover that women with a history of gestational diabetes are at a significantly greater risk of heart artery calcification, even if they maintain normal blood sugar levels after pregnancy," said co-author Erica P. Gunderson from Kaiser Permanente in California, US.
For the study, published in Circulation: Journal of the American Heart Association, the team enrolled approximately 1,100 women without Type 1 or Type 2 diabetes who subsequently gave birth at least once during the 25-year study period, which ended in 2011.
Blood tests were performed from before to after pregnancies at five-year intervals to determine if women had normal blood sugar levels, intermediate elevations in blood sugar levels (pre-diabetes) or they had developed overt Type 2 diabetes.
Heart scans were performed to measure coronary artery calcium, a strong predictor for heart disease, at exams 15, 20 and 25 years after the baseline, the first exam of the study.
At the 25-year follow-up, the participants' median age was 48 years, and 12% of the women in the study had a pregnancy complicated by gestational diabetes.
The prospective analysis found that women with a history of gestational diabetes had a two-fold higher risk of coronary artery calcification whether they had healthy blood sugar levels, pre-diabetes or Type 2 diabetes.
Of women with previous gestational diabetes, 36 per cent developed pre-diabetes and 26% developed Type 2 diabetes, compared to 35% and 9% of women with no history of gestational diabetes, the researchers said.