Heart attack risk increases during pregnancy

By Clementine Wallace

NEW YORK (Reuters Health) - Although the risk of heart attack in women of reproductive age is low, it increases three to four times in pregnant women compared with women who are not pregnant, according to a new study. Overall, the researchers estimate that 6 of every 100,000 pregnant women will have a heart attack.

The findings, published in the journal Circulation, also suggest that risk increases with age, with pregnant women over 40 years old 30-times more likely to have a heart attack than pregnant women under the age of 20.

"Even if numbers are low, this represents a dramatic increase," lead author Dr. Andra James, from Duke University Medical Center in Durham, North Carolina, told Reuters Health. "However, obstetrician-gynecologists haven't thought much about the problem."

James noted that in 2002-2003, birth rates rose six percent for women between 35 and 39 years old, and five percent for women between 40 and 44. "More and more women over the age of 35 are having children. Since risks increase with age, when a pregnant women comes in with chest pains, we can't just assume that it's not a heart attack."

James' team conducted the first national survey assessing the frequency, mortality rate and risk factors for pregnancy-related heart attacks in the United States between 2000 and 2002.

Among 12.6 million deliveries, 859 heart attacks were reported (6.2 per 100,000 pregnancies), and in 5 percent of these cases the woman died, according to the authors.

Besides age-related risk factors, high blood pressure, diabetes and smoking also increase the risk. For example, "high blood pressure increases the risk another 20 times over the three- to four-fold increase; diabetes another four times; smoking another eight times," James continued.

"For a long time we thought that estrogens are heart protective. It's only recently that the hormone has been implicated in cardiovascular diseases," she added. "We don't prescribe birth control pills to women who smoke and who are over 35, so we should also be more aggressive in counseling women on the risks associated with pregnancy."

SOURCE: Circulation, March 26, 2006.