Pre-eclampsia linked with four-fold higher risk of heart attack in decade after delivery

"The high risk of cardiovascular disease after pre-eclampsia manifests at young ages and early after delivery," said study author Dr. Sara Hallum of the University of Copenhagen, Denmark. "This indicates that interventions to prevent heart attacks and strokes in affected women cannot wait until middle age when they become eligible for conventional cardiovascular screening programmes."

Pre-eclampsia affects up to 8% of pregnancies worldwide. Medical signs are high blood pressure and protein in the urine, which develop after 20 weeks of pregnancy or soon after delivery. Symptoms include severe headache, stomach pain and nausea. "Women may mistake these for 'normal' pregnancy symptoms and thus not seek medical help until the condition becomes severe," said Dr. Hallum. "Most cases are mild, but pre-eclampsia may lead to serious complications for the mother and baby if not treated in time."

It is well established that pre-eclampsia predisposes women to an elevated likelihood of cardiovascular disease later in life. This was the first study to examine how soon after pregnancy these heart attacks and strokes manifest, and the magnitude of risk in different age groups.

National registers were used to identify all pregnant women in Denmark between 1978 and 2017. Women were grouped into those with one or more pregnancies complicated by pre-eclampsia and those with no pre-eclampsia. Participants were free of cardiovascular disease before pregnancy and were followed for a maximum of 39 years for heart attack and stroke. Dr. Hallum said: "This allowed us to evaluate exactly when cardiovascular disease occurs in women with and without pre-eclampsia, and to estimate risk in different age groups and at various durations of follow-up."

The study included 1,157,666 women. Up to 2% of those with pre-eclampsia in their first pregnancy had a heart attack or stroke within two decades of delivery, compared with up to 1.2% of unaffected women. Differences in risk became apparent seven years after delivery. "A 2% incidence of acute myocardial infarction and ischaemic stroke should not be accepted as the cost of a pregnancy complicated by pre-eclampsia, particularly considering the young age of these women when they fall ill (below 50 years of age)," states the paper.

Overall, women with pre-eclampsia were four times more likely to have a heart attack and three times more likely to have a stroke within 10 years of delivery than those without pre-eclampsia. The risk of heart attack or stroke was still twice as high in the pre-eclampsia group more than 20 years after giving birth compared to unaffected women.

When the researchers examined the risk of cardiovascular disease according to age, they found that women aged 30 to 39 years with a history of pre-eclampsia had five- and three-fold higher rates of heart attack and stroke, respectively, than those of similar age with no history of pre-eclampsia. The raised likelihood of cardiovascular disease in those with a history of pre-eclampsia persisted throughout adulthood, with women over 50 years of age still at doubled risk compared to their peers with no history of the pregnancy complication.

Dr. Hallum said: "Women are often in contact with the healthcare system during and immediately after pregnancy, providing a window of opportunity to identify those at increased risk of cardiovascular disease. The number of women with previous pre-eclampsia is large, and routine follow-up could last years or even decades. 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."