It takes a strong heart to be a mother. More women are having heart attacks during pregnancy and birth than ever, and a new study may shed light on the reasons why.
Having a baby places additional stress on the heart due to the many cardiovascular changes associated with pregnancy. During pregnancy, a woman’s blood volume increases substantially to allow for the exchange of gases and nutrients to the growing baby. Further, the amount of blood that the heart pumps each minute goes up by 30 to 40 percent. The heart itself increases in size by 10-12%. For healthy women, these changes often go unnoticed.
However, a new study has found that the risk of having a heart attack continues to increase for American women. In fact, researchers from the NYU School of Medicine have found that the risk of suffering a heart attack while pregnant, giving birth, or in the postpartum period rose by 25% in only 12 years.
For the study, the researchers analyzed data from close to 50 million pregnancy-related hospitalizations between the years of 2002 and 2014. A total of 4,471 women had an acute myocardial infarction, or heart attack, during pregnancy.
Of these women, 922 had heart attacks while pregnancy, 1061 had one during labor and delivery, and 2390 had them in the postpartum period. Overall, 1 in every 12,400 women suffered heart attacks during this time, and 4.5% of these women died as a result.
The researchers identified the following three possible reasons for the increase in the prevalence of heart attacks:
1. Many Women Are Waiting Until They Are Older to Have Children
According to a press release, the researchers believe that the trend among many women to wait to have children until later in life is one reason for the increase in heart attack risk. As we age, our risk of cardiovascular problems increases. In fact, a pregnant woman in her late 30s has a five times greater risk of heart attack than if she were in her 20s. Further, a woman in her early 40s is ten times more likely to have a heart attack than if she were pregnant in her 20s.
2. More Women are Obese and Have Other Health Conditions
Researchers point to the increasing obesity rate and higher prevalence of co-morbidities associated with obesity, such as diabetes, as one possible reason for the increase in heart attacks during pregnancy. A 2015 study found that women who are obese during pregnancy may die earlier or have an increased risk of heart problems later in life.
3. Heart Attacks Are Now Easier to Detect
Researchers admit that there may be a margin of error in the study, stating that more women may have suffered heart attacks previously, but they may not have been captured accurately. According to the study authors, heart attacks are easier to detect now, thanks to technological advances, than they were in the past.
“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 study author and cardiologist Sripal Bagalore, MD, in a press release.
While the overall incidence of heart attacks during pregnancy remains low, the fact that deaths have not decreased despite technological advances is alarming.
“Our findings highlight the importance to women considering pregnancy to know their risk factors for heart disease beforehand,” says cardiologist and first author Nathaniel Smilowitz. “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.”