Are multiparous women at risk of CVD?

Data from a study presented at the American College of Cardiology’s 63^rd Annual Scientific Session raise the intriguing question of whether multiparity raises the risk of cardiovascular disease (CVD) in women. The report, by researchers from the University of Texas Southwestern, suggests that plaque in the heart and arterial thickening may be more prevalent in women who give birth four or more times than in those with two to three live births.

The reasons for the possible link remain unclear and curiously, the relationship was a U-shaped curve, with increased evidence of subclinical atherosclerosis found in women who had no live births or just one.

The findings are based on analysis of data from the Dallas Heart Study, a multiethnic population-based cohort. The 1644 women represented in the study self-reported information about their number of live births and the investigators also assessed relevant imaging data from the participants. The average age of the women at time of analysis was 45 years and 55% were African-American.

Presence of subclinical atherosclerosis in the heart and artery walls was determined based on coronary artery calcium (CAC) scores, which were measured using computed tomography, and aortic wall thickness (ATW), which was assessed with magnetic resonance imaging. CAC was positive if it was greater than 10 and AWT was abnormal if it was greater than the 75^th percentile for age and gender. This is the first study to look at two markers of subclinical atherosclerosis.

A two-fold increased risk of an abnormal CAC or AWT was seen in women who had given birth to four or more children, compared with those who had two or three live births. The relationship was unaffected by adjustment for socioeconomic status, education, race, or factors known to increase risk of CVD. The multiparous women were more likely to be older, Hispanic and to have higher blood pressure and body mass index and to be of lower socioeconomic status.

Lead investigator Monika Sanghvi, MD, urged caution in interpretation of their findings: “This is not a recommendation for women to only have two or three children. 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.”

The researchers speculated that their population may have included women with underlying complications of pregnancy that predisposed them to CVD. The also noted that the survey instrument they used did not allow for differentiation between women who had chosen not to become pregnant and those who were unable to become pregnant for other reasons.

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