Although more women are waiting until they are older to have children, a new study conducted by researchers at UCLA has found that the risk of cardiovascular disease in pregnancy increases the older a women is when she conceives her first child.

According to the study, published in the journal Basic Research in Cardiology, these women often have higher levels of cholesterol, are generally less physically active, and are more likely to develop diabetes and heart disease.

During pregnancy, the heart usually functions better. In this study, the researchers found that rodents who experienced heart attacks during the last few months of pregnancy had worse heart function and more damaged heart tissue than non-pregnant females who suffered a heart attack.

Dr. Mansoureh Eghbali, an assistant professor of anesthesiology at the David Geffen School of Medicine at UCLA, and senior author of the study, explained:

“This very early study may help us identify and better understand the mechanisms involved in the higher risks of heart disease during pregnancy and may provide new opportunities to better treat pregnant women with cardiovascular complications and risk factors.”

The team evaluated heart differences after heart attacks among non-pregnant rats and pregnant rats in their third trimester. According to the researchers, pregnant rats only showed a 10% restoration of heart function vs. 80% among the non-pregnant rats. In addition, damaged heart tissue was almost four times higher in the pregnant rats than the non-pregnant ones.

First author of the study, Dr. Jingyuan Li, a postdoctoral fellow in the department of anesthesiology at the Geffen School of Medicine, said: “We observed worse heart function and a greater area of damage in hearts from the late-pregnancy group, compared to the non-pregnant group.”

Eghbali explained: “These findings show that the heart in late pregnancy may be particularly vulnerable to the type of injury caused by a heart attack.”

However, the team discovered that heart function among pregnant rats was partially restored only one day after giving birth, and was almost fully restored after one week.

The team set out to determine what mechanisms were responsible for the heart’s inability to effectively recover after a heart attack in late pregnancy. After a heart attack, the reintroduction of blood to the oxygen-starved tissue can occasionally result in problems (reperfusion injury), such as a sudden increase in oxygen radicals that cause cell damage.

They discovered that in late pregnancy, several components of this process are especially aggravated. These include the dysfunction of mitochondria, key cellular sub-units involved in cell death, and a decrease in signaling proteins, which protect the heart against reperfusion injury.

The next step for the team will be to gain new insights into why the risk of coronary heart disease is higher in late pregnancy. In addition, the researchers will explore interventions and identify candidates for drug therapy.

The study was funded by the National Institutes of Health.

Written by Grace Rattue