Pregnancy complications strongly linked to heart disease

by Carolyn Thomas  ♥  @HeartSisters

When I was about eight months pregnant with Ben, my first baby, I was diagnosed with something called preeclampsia. This is a serious condition affecting about 5% of pregnant women, identified by symptoms like sudden spikes in blood pressure, protein in the urine, severe swelling, and headaches or vision problems. It’s also women’s third leading pregnancy-related cause of death. Preeclampsia is clinically described as:

“…a disorder of widespread vascular endothelial malfunction and vasospasm that occurs after 20 weeks’ gestation”.

Whenever you see the words “vascular” or “endothelial” or “vasospasm” in the same sentence, you know you’re likely talking about the heart. And although preeclampsia typically goes away after pregnancy, its diagnosis may well be an early indicator of underlying heart conditions that may simmer for decades. In fact, studies now show that pregnant women who develop preeclampsia have more than twice the risk of having a heart attack or stroke later in life.

And that is what happened to me.  

Many years after immediate bed rest was ordered due to that preeclampsia diagnosis, I had a heart attack caused by a 99% blockage in my left anterior descending coronary artery – what doctors still call the “widowmaker” heart attack. Although it’s difficult to point to one single risk factor as the culprit, of course, cardiologists tell us that most cardiac events are 20-30 years in the making, so my timing seemed alarmingly on track.

Research suggests that our chance of  having a heart attack or stroke more than doubles if you have had preeclampsia, and it’s even higher if you’ve had it during more than one pregnancy, according to Dr. David Williams, an obstetrician at the University College London, who published those findings after doing an analysis of 25 preeclampsia studies in 2007.

When I was hospitalized with a heart attack in 2008, doctors asked me if I’d ever been a smoker, if I had  been treated for diabetes, high blood pressure, high cholesterol, if I had a family history of heart disease. But I have never been asked by my cardiologists if I’ve ever been diagnosed with preeclampsia or other pregnancy complications.

Nor was I warned when I was first diagnosed with preeclampsia that this condition would significantly increase my risk of future heart attack.

In fact, most major women’s health research studies have not asked women about their pregnancy history. Dr. Graeme Smith, professor of obstetrics and gynecology at Queen’s University in Kingston, Ontario, told the New York Times:

“The association is not readily appreciated by physicians. If you ask a cardiologist, they say: ‘I never heard of it.’

“But increased awareness about the two conditions might allow physicians to identify a woman’s heart disease risk sooner. The earlier you diagnose them, the more likely you are to prevent cardiovascular disease. This is an opportunity where people can change their future.”

When I contacted Dr. Smith about his research, he told me:

“It’s not just cardiologists who are not aware of the link between pregnancy complications and cardiovascular disease.

“We did a survey study among doctors in Ontario: most general practitioners and obstetricians don’t know of this link or at least don’t make any recommendations for follow-up. Our goal is to change all that!”

I asked Dr. Smith if we should now be adding preeclampsia and other pregnancy complications to our list of known heart disease risk factors, he replied:

“There are three times in a woman’s life when she is seen by a health care professional on a regular basis: 1. as a newborn/toddler, 2. when (if) she develops a chronic disease, and 3. when she is pregnant.

“Pregnancy is a window of opportunity to screen women for health risks to ensure health preservation and disease prevention”.

Dr. Smith tracked about 600 women after pregnancy, half of whom had preeclampsia. Dr. Smith’s study, published last year in the American Journal of Obstetrics and Gynecology, compared women from the preeclampsia group to women without the condition. His study found that  women in the preeclampsia group had higher blood pressure, LDL cholesterol, blood sugar and body mass index than the unaffected women.

Preeclampsia, in fact, increases the risk of heart disease by 2- to 3-fold.

Dr. Smith also told the New York Times last year:

“Such findings are a wake-up call, particularly because most women with preeclampsia are young, healthy women.”

Pregnant women with high cholesterol levels or blood pressure, with hyperglycemia, or those who fail a first stress test represent an emerging demographic of women at risk for heart disease. But according to cardiologist Dr. Sharonne Hayes of the Mayo Women’s Heart Clinic, the 10Q Report (which identifies the top 10 questions about women’s cardiovascular disease) suggests that these pregnant women are not the only ones at risk:

“There is growing evidence that a developing fetus exposed to this environment – above and beyond genetics – will now be at later risk for cardiovascular disease.

“There also remain issues regarding pregnant women or women of child-bearing age being excluded from clinical research trials. We don’t even know how to do CPR on a late-stage pregnant woman.”

Dr. Graeme Smith and his team at Queen’s University are in the process of starting what they call the MotHERS Program (Mother’s Health Education, Research and Screening) where they will be following up women who have complications during pregnancy that identify them as being at increased risk of future cardiovascular disease (or already having underlying cardiovascular risk factors).  These complications include:

• excess weight gain during pregnancy
• preeclampsia/gestational hypertension
• preterm birth
• growth-restricted baby
• clinically significant bleeding during pregnancy (abruption)
• the development of gestational diabetes/gestational impaired glucose intolerance

All of these complications of pregnancy, according to Dr. Smith, are linked to future cardiovascular disease.  He adds:

“Too much of health care is spent reacting to disease after it’s happened, and not enough is spent on prevention. This is a place to start!”

Research on the link between miscarriage and subsequent heart attacks also seems to confirm Dr. Smith’s work on the importance of pregnancy-related risk factors.  

A German study of over 11,000 women that was recently published in the British Medical Journal Heart found that age-adjusted heart attack risk over a 10-year follow up period appeared to rise significantly with each miscarriage, for a 4.34-fold greater risk among those with two or more miscarriages compared with those who had none.

Dr. Thomas Easterling, an obstetrician and preeclampsia researcher at the University of Washington Medical School, told the New York Times that data from such studies are “overwhelming.”

Most researchers do not believe that complications of pregnancy such as preeclampsia directly increase the risk of heart disease by themselves. Dr. Smith explained that it seems more likely that preeclampsia, for example, is an early indicator of the health of a woman’s heart. He called pregnancy a type of “stress test”, adding:

“How much or how badly you fail that stress test really is an indicator of your future health risk.”

Women with preeclampsia and other pregnancy complications should have frequent screenings for cholesterol levels, blood sugar and blood pressure, and to seek immediate treatment if those levels are high.

Are some women more likely to develop pre-eclampsia than others?

Doctors tell us that it’s more common in a woman’s first pregnancy, and in women whose mothers or sisters also had the condition. The risk of preeclampsia is also higher in women carrying multiple babes, in teenage mothers, and in women older than age 40. Other women at risk include those who already had high blood pressure or kidney disease before they became pregnant. The cause isn’t precisely known.

But some physicians, like New York City sleep specialist Dr. Steven Park, author of the book Sleep Interrupted, believes that sleep-breathing problems may actually be a largely unrecognized culprit here. He claims that since 99.9% of western medicine is based on studies that occur only in the daytime, it’s not surprising that sleep may be a common denominator among many medical conditions, including both preeclampsia and heart disease. He adds:

“We know that the rapid weight gain during pregnancy is a major risk for sleep apnea. One protective aspect of pregnancy is that progesterone increases significantly during pregnancy. Progesterone is a powerful upper airway muscle dilator as well as a respiratory stimulant. Sometimes the weight gain can overwhelm the protective effects of progesterone, and sleep-breathing problems can surface. In many cases obstructive sleep apnea can develop, but more often than not, the severity and duration of these breathing pauses won’t be long enough to be called apneas on formal sleep studies.”

Besides getting a sleep function test as Dr. Park would advise, there may be something you can do to help reduce your risk for preeclampsia:

• Get early and regular prenatal care. Early treatment of preeclampsia may prevent eclampsia (an acute and life-threatening condition leading to convulsions and coma).
• If you have chronic high blood pressure, keep it well-controlled during pregnancy.
• Get your doctor’s approval before taking any prescription or over-the-counter medicines.
• Do not smoke (ever!) or drink alcohol during pregnancy.
• Get regular exercise and keep weight gain within normal pregnancy limits.
• Eat regular, healthful meals and take prenatal vitamins with folate.

If you’ve been diagnosed with preeclampsia, visit The Preeclampsia Foundation’s excellent website, and please participate in their Preeclampsia Registry, a research tool that will help investigators longitudinally track women like me who have ever had preeclampsia.

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NOTE FROM CAROLYN: I wrote more about pregnancy complications and other cardiac risk factors in women in my book, “A Woman’s Guide to Living with Heart Disease” . You can ask for it at your local library or favourite bookshop, or order it online (paperback, hardcover or e-book) at Amazon, or order it directly from my publisher, Johns Hopkins University Press (use the code HTWN to save 20% off the list price).

See also:

What women need to know about pregnancy complications and heart disease

Pregnancy: the Ultimate Cardiac Stress Test

Problems In Pregnancy Signal Future Health Risks in the Wall Street Journal.

Read the New York Times piece in which Dr. Graeme Smith was interviewed.

Yet another cardiac risk calculator? My response in the British Medical Journal (and not one question about a woman’s history of pregnancy complications!) 

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♥   NEWS UPDATE: February 15, 2011 The American Heart Association has released updated guidelines for preventing cardiovascular disease in women, including for the first time ever new warnings that those women who have experienced pregnancy complications, such as preeclampsia, gestational diabetes, or preterm birth, should have those factors taken into account when their heart disease risks are evaluated later in their lives.

♥  NEWS UPDATE: August 26, 2011  An article published online in the European Journal of Cardiovascular Prevention & Rehabilitation reported that early preeclampsia (before 32 weeks of gestation) more than tripled a woman’s odds of hypertension before age 40.

♥  NEWS UPDATE: March 14, 2012   A University of Texas study published in the journal Public Library of Science One reveals that women who give birth to babies who are underweight at full term are twice as likely to develop ischemic heart disease as other women, about the same amount of risk as having high blood pressure or diabetes, even when adjusting for all other risk factors.

♥  NEWS UPDATE: January 25, 2016  The American Heart Association released its first ever scientific statement on women’s heart attacks, confirming the link between a number of pregnancy complications and subsequent risk of heart attack, adding: “compared to men, women tend to be undertreated“, and including this finding: “While the most common heart attack symptom is chest pain or discomfort for both sexes, women are more likely to have atypical symptoms such as shortness of breath, nausea or vomiting, and back or jaw pain.”

♥ NEWS UPDATE: February 19, 2019  Dr. Graeme Smith’s updated research found that women with an even wider range of pregnancy complications including placental abruption and stillbirth, are at increased risk of future cardiovascular disease. “The findings support the need for assessment and risk factor management beyond the postpartum period”; published in The American Heart Association journal, Circulation, Vol 139, Issue 8, February 19, 2019