Acute myocardial infarction (AMI) during pregnancy increased by 25 percent over a 12-year period, researchers reported in the Mayo Clinic Proceedings.
“Our analysis, the largest review in a decade, serves as an important reminder of how stressful pregnancy can be on the female body and heart, causing a lot of physiological changes, and potentially unmasking risk factors that can lead to heart attack,” said lead author Sripal Bangalore, MD, MHA, of the New York University (NYU) School of Medicine in a prepared statement issued by NYU Langone Health.
Bangalore and colleagues analyzed data for almost 50 million births in U.S. hospitals. They found 4,471 cases of AMI occurred in patient group they studied. More than 1,000 of the AMI cases occurred during labor and delivery, 922 women were hospitalized for AMI while pregnant and 2,390 cases of AMI occurred during puerperium—the six-week recovery period after birth.
The researchers also found the deadliest type of AMI, ST-segment elevation myocardial infarction (STEMI) occurred in 42 percent of cases, while non-STEMI events occurred in almost 58 percent of cases.
The researchers highlighted AMI both during pregnancy and the puerperium increased significantly with maternal age. In patients with advanced maternal age, which was defined as women 35 years and older, 23 AMI cases occurred per 100,000 hospitalizations during pregnancy. Women with gestational diabetes and preeclampsia were more likely to have AMI.
Some 203 women died in the hospital after AMI that occurred during pregnancy and the puerperium. In-hospital mortality, the researchers noted, was significantly higher in patients with AMI than in those without. And mortality rates in patients with pregnancy-related AMI remained stable over time at 4.5 percent.
The rate of AMI during pregnancy and the puerperium increased by 25 percent over a 12-year period between 2002 and 2014.
The researchers called the incidence of AMI cases in pregnancy “remarkable,” because it was occurring in spite of a decrease of cardiovascular risk in the past decade. And while several factors can potentially contribute to AMI during pregnancy, one factor stands out from the rest—advanced maternal age.
“There are a number of plausible explanations for these trends. Greater numbers of patients with advanced maternal age may underlie some of the trends in AMI reported in this analysis, as the mean age at hospitalization for labor and delivery increased over time," the authors wrote. "In the present study and in previous reports, advanced maternal age is strongly associated with AMI during pregnancy, with up to a 30-fold increased odds in women 40 years or older in comparison to pregnant women younger than 20 years.”
Bangalore et al. concluded additional research is needed on the prevention of AMI during pregnancy and puerperium and if AMI does occur, there should be optimal management of it to prevent mortality. Additionally, the researchers remarked women should know their cardiovascular risk factors well in advance to potentially control the risk for developing AMI during pregnancy.
"Our findings highlight the importance to women considering pregnancy to know their risk factors for heart disease beforehand," said first author Nathaniel Smilowitz, MD, of NYU Langone. "These patients should work out a plan with their physicians to monitor and control risk factors during pregnancy so that they can minimize their risk."
As a senior news writer for TriMed, Subrata covers cardiology, clinical innovation and healthcare business. She has a master’s degree in communication management and 12 years of experience in journalism and public relations.