Pregnancy increases a woman's risk of heart attack, and the risk persists for up to 12 weeks after delivery, researchers said this week at the annual scientific sessions of the American College of Cardiology meeting in Chicago.
Although the risk of a heart attack during pregnancy is very low – just 1 in every 16,000 deliveries – it was still 3 to 4 times higher in their study than in non-pregnant women of the same age, they said.
Hormonal changes, increased blood volume and other physiological changes increase the risk, said Dr Uri Elkayam of the University of Southern California in Los Angeles and colleagues.
And the mortality rate - 7% -- was 2 to 3 times higher than what is expected in non-pregnant women the same age.
Attacks happen for different reasons
Heart attacks during pregnancy tend to be more severe and lead to more complications, the researchers said.
They studied 150 cases of heart attacks in pregnant women that occurred since 2005.
The team found that heart attacks happen for different reasons in pregnant women than those commonly seen in the general population. Most of the pregnant women did not have traditional cardiovascular risk factors.
Clear guidelines for heart attacks
Atherosclerosis caused only a third of heart attacks, whereas in roughly 40% the infarctions were due to dissections of the coronary arteries.
This suggests that in at least some cases, the traditional approach to treating the condition during pregnancy and postpartum may not always be best, researchers said. For instance, they said, coronary dissection may be worsened by thrombolytic therapy.
"We have very clear guidelines for heart attack 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," Dr Elkayam said.
(Reuters Health, March 2012)