Washington, March 30 (IANS): Pregnancies might affect your heart as researchers have found that giving birth to four or more babies increases risks of heart diseases in women compared with those having fewer pregnancies.

The study looked at two markers of sub-clinical atherosclerosis -- a gradual narrowing and hardening of the arteries that can eventually block blood flow and lead to stroke and heart attack.

"Our findings add to the growing body of evidence that the changes associated with pregnancy may provide insight into a woman's future cardiovascular risk and deserves further attention," said Monika Sanghavi, chief cardiology fellow at the University of Texas Southwestern Medical Center.

The study included 1,644 women who had both self-reported information about the number of live births and relevant imaging study data available.

The average age at the time of analysis was 45 years and slightly more than half of the women (55 percent) were African-American.

Coronary artery calcium (CAC) scores were measured using computed tomography imaging and aortic wall thickness (AWT) by magnetic resonance imaging to determine whether or not women had evidence of sub-clinical atherosclerosis in the heart and artery walls.

CAC was positive if it was greater than 10 and AWT was abnormal if it was greater than the 75th percentile for age and gender.

Women who had given birth to four or more children had an approximately two-fold increased risk of having abnormal CAC or AWT, the study concluded.