The Link Between Pregnancy Complications And Heart Health: What You Need To Know

Complications such as high blood pressure, gestational diabetes and hypertensive disorders could indicate that a woman is at higher risk of a heart attack later in life.
By Christina Frangou
The Link Between Pregnancy Complications And Heart Health: What You Need To Know

The morning after her 58th birthday party, Carolyn Thomas woke at the crack of dawn. She wrote a stack of thank-you cards to guests and set out to slip the envelopes into the mailboxes of her still-sleeping neighbours. Somewhere between the fifth and sixth houses on her list, she felt a sudden pain shoot down her left arm, accompanied by a wave of nausea so strong she fought the urge to vomit on the sidewalk of her Victoria neighbourhood. Sweating, she grabbed onto a tree and leaned against it, unable to move.

Thomas’ symptoms lessened after about 20 minutes. She started walking, slowly, to a nearby hospital. After some “normal” cardiac diagnostic tests, an emergency physician told to follow up with her family doctor and get medications for acid reflux. Thomas apologized, embarrassed she’d made a fuss over what appeared to be a case of post-party indigestion.

Over the next weeks, Thomas swallowed multiple antacid tablets daily. Her symptoms worsened. She flew to Ottawa for her mom’s 80th birthday and endured two severe episodes of pain in the airport. She spent the flight home curled in her seat, consoling herself that it was just severe indigestion.

The next morning, back in the emergency department, she was diagnosed with having a heart attack.

For years, associations like The Heart and Stroke Foundation have been raising awareness about heart attacks in women, emphasizing that symptoms present differently in women than in men. But one important issue is rarely discussed: that complications during pregnancy could indicate that a woman is at higher risk for heart attacks, even long after pregnancy.

“Everybody asked me the standard cardiac risk factor questions.,” recalls Thomas, 68, of her time recuperating in the cardiac intensive unit. ‘What’s your family history? Do you smoke?’ But not one person ever said, ‘have you ever had pregnancy complications?’

Experts say pregnancy is too often overlooked as an indicator of women’s heart health — an omission that can have serious consequences. Evidence tying some pregnancy complications to cardiovascular disease dates back more than three decades, when several studies linked preeclampsia — which Thomas experienced with her first pregnancy — to later development of high blood pressure.

In 2005, three years before Thomas’ heart attack, Canadian researchers reported in a large population study published in The Lancet that women with certain pregnancy complications face a substantially increased risk of premature heart disease.


Since then, multiple studies have confirmed this association: women who’ve had a hypertensive disorder of pregnancy (HDP) — a group of diseases including preeclampsia (dangerously high blood pressure that usually begins after 20 weeks of pregnancy in women with previously normal blood pressure), eclampsia (seizures that develop after preeclampsia), gestational hypertension and chronic hypertension — or those who deliver low-birthweight children have twice the risk of cardiovascular disease compared to other women. Women with HDP have a nearly four-fold increase in chronic hypertension, a 4.2-fold increase in the risk of heart failure, double the risk of coronary heart disease and mortality, and an 81 percent increase in the risk of stroke compared to women with normal pregnancies.

Other pregnancy complications associated with increased risk of cardiovascular conditions include: high blood pressure, babies born with a birth weight below the 10th percentile, placental abruption, premature delivery and diabetes in pregnancy. To give some idea of the numbers of those affected, 5 to 10 percent of Canadian women will have these complications — and when it comes to continuity of care, studies clearly show there is disagreement between prenatal care providers and family doctors about what information is passed between them, and the frequency with which information is given.

Thomas learned about the link a year after her heart attack when she read about Canadian research led by Dr. Graeme Smith, professor and head of obstetrics and gynecology at Queen’s University, in the newspaper. “I thought ‘Oh my God — that is me!’”

Smith has been sounding the alarm on cardiovascular disease in postpartum women for about 20 years.

“Pregnancy is essentially a stress test. It's an opportunity, if you have one of these complications, to talk about what can be done to potentially prevent future cardiovascular problems, but also prevent problems from arising in the next pregnancy.”


Too few healthcare providers are aware of this association and even fewer follow up with women after pregnancy to screen for risk factors of cardiovascular disease, he said. In 2007, only 50 percent of obstetric providers in Ontario were aware of the risk, in a survey done by Smith and colleagues. Ten years later, a similar survey of Canadian physicians from various specialties found only 42 percent knew that women with preeclampsia have increased risks of subsequent heart disease and stroke — OB/GYNs were the most aware at 53 percent; cardiologists and primary care physicians trailed behind at 39 percent.

“Since then, the word is slowly getting out there among health care providers but we’ve still a long way to go,” said Smith.

This knowledge gap can have serious consequences for women’s health, says Dr. Amy Metcalfe, a Calgary-based epidemiologist who specializes maternal health. When women know they face an elevated risk of cardiovascular disease, they can make lifestyle changes — things like increasing exercise or starting medications when appropriate. Even if screening tests postpartum reveal no other risk factors, women who’ve had these pregnancy complications should be vigilant for heart attack symptoms, said Metcalfe.

“Be aware that these things that have happened in pregnancy may actually increase your risk down the road and when something doesn’t feel right, really push for further investigations and further tests,” she said.

“As you age, if you have signs of disease or if something doesn’t feel right — even if you can’t necessarily put your finger on it — listen to your body. A lot of the time, the symptoms of (cardiovascular disease) are general feelings of unwell or headache or a little bit of dizziness. They’re mild symptoms that people wouldn’t necessarily seek out treatment for.”


Ignoring the symptoms of heart disease can be deadly. Heart disease is the number one killer of women in Canada, and women are 16 per cent more likely than men to die after a heart attack. Many will develop heart disease without having any of the well-known risk factors — things like smoking, obesity and diabetes.

How can something potentially so important for women’s health be so poorly known? Experts who study this point to a myriad of causes. Heart disease among women has historically been understudied and overlooked; most factors associated with heart disease are derived from studies consisting mostly of men. As a result, few cardiac risk calculators — tools that health care professionals regularly use to assess a person’s individual risk for cardiovascular disease — take into account pregnancy complications.

Postpartum care is too often neglected by the healthcare system — a failing highlighted in a number of recent high-profile cases. Serena Williams told Vogue magazine that she’d experienced life-threatening complications when healthcare workers underplayed her concerns about blood clots, ignoring her requests for tests. Pregnancy is often viewed as an event unto itself; a misperception persists that complications resolve after giving birth.

Another challenge, says Dr. Kara Nerenberg, an assistant professor in obstetrics and gynecology also in the department of medicine at the University of Calgary, is that pregnant and post-partum women cross various areas of medicine: “they cross obstetrics, they cross primary care, and also cardiology and neurology. In those gaps, that’s probably where some of the messaging is dropped.”

Nerenberg is currently conducting studies on prevention of cardiovascular disease in post-partum women. Two theories exist about what happens in women’s bodies during pregnancy that leaves them vulnerable to cardiovascular conditions down the road, she said. The first: the physical stress of pregnancy unmasks the earliest symptoms of a chronic disease that’s already quietly underway. The other posits that pregnancy initiates cardiovascular problems when an unhealthy placenta produces proteins that circulate in the blood and damage blood vessels.


Why this happens is just one of many unanswered questions about the relationship between pregnancy and cardiovascular disease, she said. But while the scientific community is looking for answers, “it doesn’t mean that we do nothing.”

“We still need to treat these women. I would encourage women to strike up this conversation with their care providers and really take ownership of their health. (It)’s something that is preventable and we really, really can do better in that area.”

Smith urges doctors to start screening women for cardiovascular risk factors six months postpartum — waiting any longer could potentially result in irreversible harm in the long term. The screening should include a series of biochemical tests, based on recommendations by the Canadian Diabetes Association and the Canadian Lipid Guidelines, as well as a detailed personal and family history, he said.

And when physicians don’t offer screening, women should ask for it — even if it’s been years since their pregnancy, he advised. “If a woman has had a complication in the past and they’re well out from pregnancy, I think it’s still completely reasonable to be screened for some of these things.”

In 2011, Smith launched North America’s first Maternal Health Clinic in Kingston. Its goal is two-fold: reduce long-term heart disease and improve any future pregnancy outcomes for at-risk women. In the five years since he opened his clinic, another nearly dozen more have launched in Canada and the United States.


In the 12,000-person town of Prince Rupert, BC, Dr. Marius Pienaar runs a similar clinic—the smallest site that offers this service. They screen every single mother who delivers one of the approximately 200 babies born in the town each year. Doctors across Canada could and should be doing this, he said.

“The whole female population of the country, with very few exceptions, we get to see them in the middle of their lives because of pregnancy. We can catch them, and at an early stage, to have an intervention.”

Four years ago, then 22-year-old Jaymee Davis of Kingston developed severe preeclampsia during her third pregnancy. At 36 weeks, she was told the baby needed to come right away as her blood pressure had spiked. “Delivery is the cure,” she remembers doctors and nurses telling her.

But that wasn’t the case. Her blood pressure continued to climb in the weeks following. Davis remained on blood pressure medications for another two months — an astonishment to the long-time vegetarian and non-smoker.

Since then, she has monitored her heart health closely, ramping up her exercise program and watching her stress levels. “After learning about the cardiovascular risks I have now, I began working out about five months after the delivery... Working out, as annoying as it can be, is now not an optional task.”


With more women postponing pregnancy to older ages, more women today have chronic diseases by the time of their first pregnancy — with higher rates of diabetes, hypertension and gestational diabetes. This means an even greater potential for cardiovascular disease among women in future. “If the incidence of pregnancy complications is increasing, this may be an early warning sign of increasing rates of cardiovascular disease in upcoming years,” said Metcalfe.

Since her heart attack, Thomas advocates for better awareness of women’s heart health, speaking at small community events and large national meetings for physicians. Her book, A Woman’s Guide to Living with Heart Disease, was published by John Hopkins University Press in 2017.

She offers this advice to all women: “This could be your mom, your sister, your next-door neighbor. If you or they have had any one of this long list of cardiac complications, go see your doctor and ask that you be referred to a cardiologist.”


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