Heart attack during pregnancy, labor or delivery occurs rarely, but the rate has increased in the last 10 years, according to a study conducted by a team from the University of California-Davis. The trend seems to be related to the increase in maternal age.

Dr. Heidi E. Ladner, who led the study, told AMN Health that one of the “most interesting observations” in their study was the link between heart attack and older maternal age, pre-existing diabetes and high blood pressure, as well as pregnancy-related blood pressure disorders.

In a report published in the medical journal Obstetrics and Gynecology, Ladner and her colleagues urge healthcare providers to be aware of the risk factors associated with heart attack during pregnancy and to conduct diagnostic testing to identify and treat women at high risk.

During the 10-year period spanning January 1, 1991 to December 31, 2000, California state maternal and newborn discharge records contained a total of 15 heart attacks in 5.4 million deliveries, yielding an incidence of 1 heart attack in 35,700 pregnancies.

According to the investigators, the incidence of heart attack rose from 1 in every 73,400 pregnancies at the start of the decade to 1 in every 24,600 pregnancies at the end of the decade.

Compared with women who did not have heart attacks, those who did were more likely to be older (66 percent were older than age 30 and 7 percent were older than 40), have multiple pregnancies, to be non-Hispanic white or African American and to have a higher rates of other illness.

High blood pressure - either preexisting or pregnancy-related - was significantly increased among women who had heart attacks.

Although the cause could not be determined in this study, the findings suggest that physicians should have a higher level of suspicion of heart attack during pregnancy and in the postpartum period for women with diabetes or high blood pressure, Ladner said.

Most of the heart attacks (59 percent) occurred around the time of delivery. Overall, 11 women (7.3 percent) died from a heart attack and all of these deaths occurred in women who developed heart attack before or during delivery.

Ladner and colleagues say the rate of heart attack during pregnancy is likely to increase as more women delay child bearing, and they urge physicians to be aware of the risk factors in this patient population.

Source: Obstetrics and Gynecology, March 2005.