Acute MI during pregnancy more common in recent years

The incidence of acute myocardial infarction (AMI) in pregnant women increased between 2005 and 2014, according to research published in the American Journal of Cardiology Jan. 25, but that hike was accompanied by decreases in mortality, cost of care and length of stay among expectant mothers.

Byomesh Tripathi, MD, and colleagues used Nationwide Inpatient Sample data from 2005 to 2014 to identify 43.4 million pregnancy-related hospitalizations in an effort to gauge the current incidence of AMI in pregnant women in the U.S.

“Pregnancy-related mortality in the U.S. has steadily increased from 7.2 deaths per 100,000 live births in 1987 to approximately 17.3 deaths per 100,000 live births in 2013,” Tripathi and co-authors wrote in AJC. “Despite available information on pregnancy-related AMI and its outcomes from small, highly skilled centers, there is a constant need for population-based studies which correlate to the United States population in the ‘real world.’”

Of the tens of millions of hospitalizations they initially considered, the researchers identified 3,786 cases of AMI during the study period—an incidence of 8.7 AMIs per 100,000 pregnancies with an overall 18.9 percent increase between 2005 and 2014. Fourteen percent of AMIs were postpartum; 86 percent were antepartum.

The authors also noted parallel decreases in mortality (40 percent), cost of care (8.7 percent) and length of stay (13.5 percent) in women who suffered an AMI. They said black race, comorbidities like hypertension and diabetes, substance abuse and postpartum complications like hemorrhage and depression all seemed to predict AMI in pregnant women, but older age was a major risk factor. Mothers over 40 years old had a more than tenfold increased risk of AMI.

“Association of rising age with AMI in pregnancy has been noted before, but a more than tenfold risk in the age group over 40 years hasn’t been reported,” Tripathi et al. wrote. “This is an important finding as a rise in mean age of pregnancy and birth rates among the age group 40-44 years is expected to bring increased healthcare cost burden in the United States.”

Due to database limitations, the authors said they weren’t able to track long-term outcomes of pregnancy-induced AMI in the study population. They weren’t able to estimate AMI-related fetal mortality for similar reasons, but said their study is one of the largest of its kind and provides “real-world representation.”

“We noted an increasing incidence of AMI during pregnancy in recent years, but with concomitant improvement in mortality and resource utilization,” Tripathi and co-authors wrote. “Overall, these findings point toward improvement in diagnostic and treatment approaches.”