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 blocked 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.(1) That’s about the same amount of added risk as having high blood pressure or diabetes, even when adjusting for all other risk factors.

When I was hospitalized with a heart attack in 2008, every doctor and nurse in the CCU (the intensive care unit for heart patients) asked me if I’d ever been a smoker, if I had a family history of heart disease, and if I’d been treated for diabetes, high blood pressure, or high cholesterol. But I have never been asked by any health care professional, then or since, 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. Few if any medical researchers were even aware of this association at the time.

In fact, I didn’t find out about this now-recognized link between my own preeclampsia and subsequent heart disease until a year after I survived that heart attack. That’s when I happened to read a The New York Times interview with a Canadian physician who had been researching this link.(2)

Dr. Graeme Smith, professor of obstetrics and gynecology at Queen’s University in Kingston, Ontario, told The Times:

“The association is not readily appreciated by many 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!”

During that first interview with Dr. Smith, preeclampsia and other pregnancy complications were not included on any major list of known heart disease risk factors.

In fact, it wasn’t until 2011 that American Heart Association released updated guidelines for preventing cardiovascular disease in women, including for the first time ever new warnings that high-risk 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:

“Appropriate referral postpartum by the obstetrician to a primary care physician or cardiologist should occur so that in the years after a high-risk pregnancy, cardiac risk factors can be carefully monitored and controlled.

“Healthcare professionals who meet women for the first time later in their lives should take a careful and detailed history of pregnancy complications with focused questions about a history of gestational diabetes mellitus, preeclampsia, preterm birth, or birth of an infant small for gestational age.”

Dr. Smith adds:

“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
• 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 reminds women that pregnancy complications may be some of the earliest identifiable heart disease risk indicators available.

So if you are or have been pregnant, it’s important that you discuss with your doctor any complications you may have experienced. These include:

• Preeclampsia:  a serious and potentially fatal pregnancy complication characterized by high blood pressure and protein in the urine. Increases risk of placental abruption. It’s important to monitor your blood pressure after delivery to make sure it returns to a safe level.

• Gestational Hypertension:  consistently high blood pressure during pregnancy marked by an absence of protein in the urine. It’s important to monitor your blood pressure after delivery to make sure it returns to a safe level.

• Gestational Diabetes:  high blood sugar that starts during pregnancy, usually diagnosed between the 24th and 28th week of pregnancy through the glucose challenge test. Some cases can be managed with dietary changes, others could require medication.

• Gestational Impaired Glucose Tolerance: commonly referred to as pre-diabetes, identified in the same way as gestational diabetes. Managed through dietary changes.

• Placental Abruption:  a condition in which the placenta separates from the uterus before delivery. Fetal distress and vaginal bleeding can range from mild to severe. If this condition suspected, requires urgent assessment.

• Excessive Weight Gain:  determined based on your pre-pregnancy Body Mass Index (ppBMI).
  • if ppBMI less than 18.5 – weight gain of 40lbs or more is excessive
  • if ppBMI 18.5 to 24.9 – weight gain of 36lbs or more is excessive
  • if ppBMI 25.0 to 29.9 – weight gain of 25lbs or more is excessive
  • if ppBMI greater than 29.9 – weight gain of 20lbs or more is excessive

• Preterm Birth:  delivery before 37 weeks gestation, occurs in 7.1% of all pregnancies greater than 20 weeks gestation.

• Intrauterine Growth Restriction:  refers to poor growth of the baby during pregnancy resulting in full-term but low birth weight, may be diagnosed before delivery based on ultrasound, or after delivery based on baby’s gestational age and weight.

All of these complications of pregnancy, according to Dr. Smith, are linked to higher risk of 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. But this is a place to start!”

Dr. Smith’s own research tracked about 600 women after pregnancy, half of whom had preeclampsia. His study, published in the American Journal of Obstetrics and Gynecology, compared women from the preeclampsia group to women without the condition.(1) He found that women in the preeclampsia group had higher blood pressure, LDL cholesterol, blood sugar and body mass index than the unaffected women. Preeclampsia, his study concluded, increases the risk of heart disease by 2- to 3-fold.

As Dr. Smith also told The New York Times:

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

We know that most major women’s health research has not asked women specifically about their pregnancy history. And pregnant women are routinely excluded from participating directly in medical research precisely because they are pregnant. According to cardiologist Dr. Sharonne Hayes, founder of the Mayo Women’s Heart Clinic, the 10Q Report (which identifies the top 10 questions about women’s cardiovascular disease) suggests that pregnant women with complications are not the only ones at risk:(3)

“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!”

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

That’s why he and his team at Queen’s University launched what they call the MotHERS Program (Mother’s Health, Education, Research and Screening) in 2010, where they will be following up local maternity patients who have complications during pregnancy that identify them as being at increased risk of future cardiovascular disease (or are already having underlying cardiovascular risk factors).  There’s even a new app for all mothers at risk, designed at Queen’s University in collaboration with the MotHERS program. It’s called Maternelle, and it lets new mothers and their healthcare providers track important maternal health indicators such as blood pressure, weight gain or loss, and other medical data directly on their phones.

When I was asked to speak about the patient’s perspective to a 2014 Toronto medical conference on preeclampsia and heart disease, I heard another speaker, Dr. Eric Steegers from the Netherlands. I loved how he described reproductive disorders like preeclampsia as “a short-term problem for the OB-GYN, but a longterm problem for the cardiologist”.

But because most women with the conditions listed above have rarely been  considered at high risk for cardiovascular disease, he warned, current cardiac treatment guidelines are not tailored to this group of young women.

Echoing Dr. Smith’s statements back in 2009, Dr. Steegers told our audience that many doctors aren’t even aware of this link.

Further research on the link between several pregnancy complications and subsequent risk of developing heart disease confirms Dr. Smith’s work on pregnancy-related cardiac risk factors. A German study of over 11,000 women published in the BMJ Heart, for example, found that age-adjusted heart attack risk over a 10-year follow up period appeared to rise significantly – by 42% – with each miscarriage, for a 4-fold greater risk among those with two or more miscarriages compared with those women who had none.

Another study by University of Texas researchers published in the journal Public Library of Science One found 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.

And a 2011 study published 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.

Most researchers do not believe that complications of pregnancy such as preeclampsia directly increase the risk of heart disease all 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 the “ultimate cardiac stress test”, adding:

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

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 teenaged 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 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 disorders are 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.”

Besides participating in a sleep study, 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. Please participate in their Preeclampsia Registry, a research tool that will help investigators longitudinally track women like me who have had preeclampsia.

♥

1. Williams D. “Pre-eclampsia and long-term maternal health.” Obstetric Medicine. 2012;5(3):98-104.
   

2. Smith, Graeme N. et al. “A history of preeclampsia identifies women who have underlying cardiovascular risk factors.” American Journal of Obstetrics & Gynecology, Volume 200 , Issue 1 , 58.e1 – 58.e8, January 2009.
   

3. WomenHeart: the National Coalition for Women with Heart Disease. “10Q Report: Advancing Women’s Heart Health through Improved Research, Diagnosis, and Treatment.” The Society for Women’s Health Research, released June 2011.

.

Q:  Have you been diagnosed with a pregnancy complication and then later heart disease?

.

NOTE FROM CAROLYN:   I wrote much more about pregnancy complications and other cardiac risk factors unique to women in my book A Woman’s Guide to Living With Heart Disease (Johns Hopkins University Press).  You can ask for it at bookstores (please support your local independent bookseller!) or order it online (paperback, hardcover or e-book) at Amazon – or order it directly from my publisher Johns Hopkins University Press (use their code HTWN to save 30% off the list price).♥

.UPDATE, June 27, 2018:  I was thrilled to be invited by OB-GYN Dr. Graeme Smith to share my patient perspective at the 74th annual Clinical and Scientific Conference of The Society of Obstetricians and Gynaecologists of Canada (SOGC) in Victoria, BC (where I live).

See also:

MotHERS Podcast™ interview with OB-GYN Dr. Graeme Smith on PostPartum Cardiovascular Health, April 2023

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 I first discovered Dr. Graeme Smith’s work