Delaying pregnancy may increase the risk of cardiovascular disease in both women and their children, with boys at higher risk of disease, according to a new study 

Researchers from the University of Alberta in Canada will present their findings today at the American Physiological Society's (APS) Cardiovascular, Renal and Metabolic Diseases: Sex-Specific Implications for Physiology conference in Knoxville, Tenn.

Previous studies have found that advanced maternal age—35 or older during pregnancy—increases the risk of impaired blood vessel function and reduced blood flow to the placenta. These issues endanger the growth and overall health of the unborn child and may contribute to heart disease later in the pregnant woman's life.

Worsened outcomes

Researchers grouped a rat model of advanced maternal age according to pregnancy status, including "never pregnant," "postpartum" and "pregnancy loss." They found the pregnancy loss group had less widening of the blood vessels (vasodilation) compared to the groups that were never pregnant or had recently delivered.

In some cases, less vasodilation may lead to decreased vascular health. In addition, the postpartum group had reduced vasodilation in the arteries of the intestines.

"These data demonstrate mechanisms which may lead to worsened outcomes at an advanced maternal age, including early pregnancy termination, and later life cardiovascular dysfunction," the research team wrote.

The researchers also found sex-specific differences in health risks of the older rats' offspring. Males born to the postpartum group had impaired function of the blood vessel lining and cardiac risk factors associated with interrupted blood flow. The female offspring did not show the same risk factors.

"Given the increasing trend toward delaying pregnancy, our findings have significant population and healthcare implications and further illustrate pregnancy as a window of opportunity to assess cardiovascular health," the researchers wrote.