Pre-eclampsia Linked to Increased Heart Attack Risk

In the decade after giving birth, women with pre-eclampsia had four-fold higher rates of having a heart attack and three-fold higher rates of stroke than women without the condition.

Pre-eclampsia is a condition that usually occurs after the 20th week of pregnancy. It is characterized by high blood pressure, swelling, and protein in the urine. If left untreated, pre-eclampsia can harm both the mother and the unborn baby and lead to a more severe condition known as eclampsia.

Previous studies suggest that women who have had pre-eclampsia during pregnancy are at increased risk of cardiovascular disease later in life. However, scientists are unclear about when a heart attack or stroke is most likely to occur after delivery. This makes it difficult to know when to begin screening and begin preventative strategies for cardiovascular disease.

To investigate this further, scientists from Denmark looked at when the risk of cardiovascular disease increases after pre-eclampsia and how the risk changes over time since the time of pregnancy. Specifically, they estimated the cumulative incidences of heart attack and ischemic stroke and hazard ratios by age and time since delivery.

The register-based study published in the European Journal of Preventive Cardiology on January 26 included 1,157,666 women with more than one pregnancy between 1978 and 2017. The scientists followed the participants for up to 39 years.

After examining the data, the research team found up to twice as many women with pre-eclampsia during their first pregnancy experienced a heart attack or ischemic stroke within 20 years of delivery compared with women who did not have the condition.

Ten years after delivery, women with pre-eclampsia had four-fold higher rates of heart attack and three-fold higher rates of stroke than women without pre-eclampsia. Moreover, these rates remained significant for over 20 years.

In addition, women with pre-eclampsia aged 30–39 years had five-fold higher heart attack rates and three-fold higher rates of stroke than women in the same age range without pre-eclampsia.

What’s more, the findings suggest that having pre-eclampsia in the second pregnancy, but not the first, was more strongly associated with heart attack risk than having pre-eclampsia in the first pregnancy but not the second.

The authors note that this result goes against the idea that an increased risk of heart attack is associated with pre-eclampsia on its own. Instead, they hypothesize that other factors, such as the excessive demands placed on the heart during subsequent pregnancies complicated by pre-eclampsia, may play a role.

In a news release, study author Dr. Sara Hallum from the University of Copenhagen, Denmark, said, "Our study suggests that the women most likely to benefit from screening are those who had pre-eclampsia after age 35 and those who had it more than once. Prevention should start within a decade of delivery, for example by treating high blood pressure and informing women about risk factors for heart disease such as smoking and inactivity."