Heart Attack Risk Going Uphill for Pregnant Women

The risk of suffering from a heart attack during pregnancy, while delivering, and in the two months post-delivery continues to increase for American women, says a new study led by NYU School of Medicine researchers and published online July 18 in the Mayo Clinic Proceedings. The definite increase in the risk of having a heart attack rose 25 percent from 2002 to 2014 for pregnant women.

The researchers suggest that increased numbers could be due to

• Many women having children later in life (heart attack risk is directly proportional with age, older women are also prone to get gestational blood pressure which is an increase that occurs only during pregnancy)
• More women are also obese and/or have diabetes when they get pregnant; obesity and diabetes are key risk factors for a heart attack
• Heart attacks or myocardial infarcts are easier to detect now than a decade ago, as tests for early protein markers of related heart cell damage have improved and are more widely available nowadays

"Our analysis, the largest review in a decade, serves as an important reminder of how stressful pregnancy can be on the female body and heart, causing a lot of physiological changes, and potentially unmasking risk factors that can lead to heart attack," says an associate professor in the Department of Medicine at NYU Langone Health and study senior investigator and interventional cardiologist Sripal Bangalore, MD, MHA.

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Study Design and Results

The researchers examined 49,829,753 births recorded in hospitals; they obtained the data from the U.S. Agency for Healthcare Research and Quality's National Inpatient Survey up until 2014 which was the last full year of available data.

They found that

• 1,061 heart attacks happened during labor and delivery
• 922 women were hospitalized for myocardial infarction before birth
• 2,390 heart attacks occurred during the recovery period after birth
• Rates for heart attack increased from 7.1 for every 100,000 pregnancies recorded in 2002 to 9.5 for every 100,000 pregnancies in 2014

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Inferences from the Study

• It might seem like the absolute numbers of heart attacks and deaths from them remain low but the relatively high death rate numbers exist in spite of advances in treating heart attacks with drug-coated stents and using blood-thinning medications to prevent heart-vessel blockages.
• The risk of having a heart attack during pregnancy increases as a woman gets older. If a woman becomes pregnant between the ages of 35 to 39, she is five times more likely to suffer a heart attack than a woman in her 20s, and if she becomes pregnant in the early 40s, she is 10 times more at risk than a woman in her 20s.
• "Our findings highlight the importance to women considering pregnancy to know their risk factors for heart disease beforehand," says study first author and interventional cardiologist Nathaniel Smilowitz, MD, an assistant professor at NYU Langone. "These patients should work out a plan with their physicians to monitor and control risk factors during pregnancy so that they can minimize their risk."

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Heart problems during pregnancy

During pregnancy a mother's circulatory system is required to provide additional blood to the uterus and the placenta; as a result, her blood volume increases. The demand on the circulatory system is huge, which may cause problems if there is underlying heart disease.

The volume of plasma (fluid in the blood) starts increasing early in pregnancy and grows at a faster rate than the rate at which the blood cells increase and soon reaches peak effects (approximately 50 percent more than the non-pregnant state) between 24 and 26 weeks. The plasma volume increase results in anemia or a lower than normal count of red blood cells during pregnancy which puts an increased demand on the heart.

Later in pregnancy, the heart rate increases between 10 and 20 percent to promote circulation of blood to the uterus. The mother experiences the highest heart rates in the last trimester. Total cardiac output (CO) is calculated as the volume of blood pumped out of the heart with each beat. With heart rate increase, the total CO also increases and is up to 50 percent in mid-pregnancy.

The above cardiac changes may cause heart problems during pregnancy, or the pregnancy itself may be affected by the underlying heart problem. Therefore, it is vital for women with heart disease to have a complete preconception evaluation done before becoming pregnant to promote a successful pregnancy outcome.

References:

1. Heart Attack Risk on the Rise for Pregnant Women & Death Rate Remains High - (https://nyulangone.org/press-releases/heart-attack-risk-on-the-rise-for-pregnant-women-death-rate-remains-high)
2. Heart Disease and Pregnancy - (https://www.nm.org/conditions-and-care-areas/cardiovascular-care/preventive-cardiology/heart-disease-and-pregnancy)

Source-Medindia