CNN
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Five major pregnancy complications are strong lifelong risk factors for ischemic heart disease, a new study finds, with the greatest risk coming in the decade after delivery.

Ischemic heart disease refers to heart problems, including heart attack, caused by narrowed or dysfunctional blood vessels that reduce blood and oxygen flow to the heart.

Gestational diabetes and preeclampsia increased the risk of ischemic heart disease in the study by 54% and 30%, respectively, while other high blood pressure disorders during pregnancy doubled the risk. Delivering a baby early – before 37 weeks – or delivering a baby with a low birth weight were associated with a 72% and 10% increased risk, respectively.

The study, published in Wednesday in the BMJ, followed a cohort of more than 2 million women in Sweden with no history of heart disease who gave birth to single live infants between 1973 and 2015.

Roughly 30% of the women had at least one adverse pregnancy outcome. Those who had multiple adverse outcomes – whether in the same or different pregnancies – showed further increased risk of ischemic heart disease.

“These pregnancy outcomes are early signals for future risk of heart disease and can help identify high-risk women earlier and enable earlier interventions to improve their long-term outcomes and help prevent the development of heart disease in these women,” said Dr. Casey Crump, an author of the study and professor of family medicine at the Icahn School of Medicine at Mount Sinai.

Heart disease is the leading cause of death among women in the United States and accounts for 1 in 5 female deaths, according to the US Centers for Disease Control and Prevention. This research adds to mounting evidence that pregnancy provides important information about a woman’s cardiovascular health.

“What happens to a woman during pregnancy is almost like a stress test or a marker for her future cardiovascular risk after pregnancy. And unfortunately, a lot of women don’t get told this by anybody,” said CNN Medical Correspondent Dr. Tara Narula, an associate professor of cardiology and the associate director of the Women’s Heart Program at Lenox Hill Hospital. She was not involved in the new study.

Although it’s not completely clear why, experts say the normal changes that occur during pregnancy may unmask underlying health issues in some women with certain risk factors.

Experiencing an adverse pregnancy outcome – even temporarily – could result in changes to blood vessels and the heart that may persist or progress after delivery, increasing a woman’s risk for cardiovascular disease.

This heightened risk is a particular concern for women in the US, experts say, where the maternal mortality rate is several times higher than in other high-income countries.

“There’s been a change in the birthing population. US women are getting pregnant at a later age, and they have already accrued maybe one or two cardiovascular risk factors. Perhaps there are other stressors in life – depression, stress, isolation, obesity – lots of different things that are impacting women in the US,” said Dr. Garima Sharma, associate professor of cardiology and director of the Cardio-Obstetrics Program at Johns Hopkins University School of Medicine, who also was not involved in the new study.

Pregnancy complications are carefully monitored during pregnancy, but there is little evaluation of and education about the effects on cardiovascular health after delivery for women, experts say.

“And so they have their delivery, they’ve had maybe preeclampsia or gestational diabetes, and nobody really follows up with them. They are not told that, in fact, they are at increased risk,” Narula said.

Gestational diabetes is a marker not only for increased risk of diabetes but also for general cardiovascular disease. Preeclampsia and eclampsia are markers for hypertension risk as well as general cardiovascular risks.

Narula, a cardiologist who specializes in caring for women, regularly considers adverse pregnancy outcomes when evaluating patients and emphasizes the continued need for this.

“The classic risk calculator that we use doesn’t have anything in there for pregnancy complications, but you know, it should for women, and hopefully someday, they will start to take that into account,” she said.

The American Heart Association recommends that all health care professionals take a detailed history of pregnancy complications when assessing a woman’s heart disease risk, but this is not consistently done in clinical practice, especially in primary care, where most women are seen, Crump says.

“Raising awareness of these findings among physicians as well as women hopefully will enable more of these women to be screened early and hopefully improve their long-term outcomes,” he said.

Roughly 1 in 3 women will have an adverse pregnancy outcome. Experts say that improving your health before getting pregnant can help avoid these issues.

“Reducing your risk should start preconception, and so getting your body and yourself into the healthiest state possible before you ever even get pregnant is really the first step,” Narula said.

This includes achieving and maintaining a healthy body weight with a good diet and regular exercise, controlling high blood pressure and diabetes, quitting smoking and managing stress.

Taking action after pregnancy is equally important, as research has estimated that only 30% to 80% of women have a postpartum checkup 6 to 8 weeks after delivery.

“Making sure that these women actually are appropriately followed after their delivery and that there is a warm handoff between [obstetrics] and [maternal-fetal medicine] to their primary care doctors or preventive cardiologists who can then talk about optimizing cardiovascular risks and reduction of these risk factors post-pregnancy in the postpartum time frame is crucial,” Sharma said.

Experts hope that increased patient and provider awareness of the connection between pregnancy and heart health will keep birth from being a cause of death.

“Cardiovascular disease is preventable. It’s a leading cause of maternal mortality, but it doesn’t have to be. If we do a better job at screening patients before they get pregnant, if we do a better job of treating them during pregnancy and postpartum, we can improve women’s outcomes,” Narula said. “It’s a tragedy to bring a new life into the world, and then the mother suffers some horrible complication and/or death that could have been prevented.”