(RxWiki News) Having a heart attack while pregnant is highly unlikely, but pregnant women are still at three to four times greater risk for an attack compared to non-pregnant women of the same age.
According to new research, pregnancy can increase the risk of experiencing a heart attack while carrying a baby and up to three months after giving birth.
"More conservative treatment is best after a heart attack during pregnancy."
More importantly, however, the way a pregnant woman is treated following a heart attack may not follow traditional guidelines for typical care of heart attacks. The causes appear to be different in pregnant women, so the best treatment is also different, possibly involving nothing more than careful observation for stable women.
Uri Elkayam, M.D., a medical professor at the University of Southern California in Los Angeles, led the study looking at rates of heart attacks among pregnant women and how these heart attacks differed from attacks in the general population in terms of the causes and outcomes.
Elkayam's team looked at 150 women who, since 2005, had experienced a heart attack while pregnant or within 12 weeks of pregnancy. Approximately one pregnant woman in 16,000 will have a heart attack.
One encouraging finding from their research was that rate of death among mothers who have heart attacks has been cut in half when they compared 228 cases before 2005 to the 150 since 2005.
Another finding, however, is that heart attacks associated with pregnancy tended to be more severe than other heart attacks, with a 7 percent rate of death, approximately two to three times greater than the rate of death in women of similar age and demographics who have heart attacks unassociated with pregnancy.
The researchers also found that the women who experienced the heart attacks did not have the typical risk factors associated with being at higher risk for an attack, including high blood pressure, diabetes or high cholesterol.
The underlying reasons for heart attacks in pregnant women also appeared to be different from those leading to a heart attack in non-pregnant people. The most common cause of a heart attack among the general population is a build-up of fat that narrows the arteries, called atherosclerosis.
But only a third of the pregnant women who had heart attacks showed atherosclerosis. Rather, most had a typically rarer condition called coronary dissection, in which a tear in the coronary artery forces apart the layers of the artery wall and blocks blood flow.
This coronary dissection, which may be caused by the women's hormone levels weakening the coronary artery wall, could be further aggravated through some of the standard treatments used in heart attacks, such as one called thrombolytic therapy.
The researchers concluded, therefore, that the cause of a pregnant woman's heart attack should be determined before doctors treat her so that they do not unintentionally worsen the situation.
“We have very clear guidelines for treating myocardial infarction in the general population. These guidelines, however, may not always apply to women with pregnancy-associated heart attacks, and may actually cause more harm than good,” Elkayam said.
Elkayam suggests that doctors use coronary angiography to find out what caused a heart attack and to use "guide therapy" if a high-risk patient needs treatment immediately.
For low-risk or stable pregnant women, however, he suggested doctors be very cautious about the extent to which they treat heart attacks at all. This suggestion grew from the evidence that some patients in their study who underwent coronary angiography or angioplasty then experienced a coronary dissection as a result of these tests and either died or required surgery or a stent.
The research was presented at the American College of Cardiology's 61st Annual Scientific Session in Chicago on March 25. Information regarding funding or financial disclosures was unavailable.