Incidence of acute myocardial infarction (AMI) continues to increase in women during pregnancy and the puerperium. Data from a new study published in Mayo Clinic Proceedings, point to underlying factors contributing to that trend.
The findings are from an analysis of data taken from the Agency for Healthcare Research and Quality’s Healthcare Cost and Utilizations Project National Inpatient Sample database. Women aged 18 or older who were hospitalized with AMI during pregnancy and the puerperium between January 1, 2002 and December 31, 2014 were represented in the study.
A total of 4471 cases of AMI (8.1 [95% CI, 7.5-8.6] per 100,000 hospitalizations during pregnancy) occurred during the study period. Of these, 922 AMI cases were identified in the antepartum period, 1061 cases occurred during hospitalizations for labor and delivery, and 2390 AMI cases occurred in the postpartum period. Between 2002 and 2013, the rate of AMI that occurred in hospitalizations during pregnancy and the puerperium increased over time (from 7.1 cases per 100,000 hospitalizations during pregnancy in 2002-2003 to 9.5 cases per 100,000 hospitalizations during pregnancy in 2012-2013; P< 0.001).
Age was found to be significantly associated with AMI risk. Women with pregnancy-related AMI were older than those without AMI (mean age, 33.1 years vs 28.0 years; P < 0.001) and were likelier to have cardiovascular comorbidities. In patients with advanced maternal age (≥ 35 years), 23.3 (95% CI, 21.1-25.6) AMI cases occurred per 100,000 hospitalizations during pregnancy.
The proportion of AMI cases was highest among women who had any preexisting coronary artery disease (CAD) risk factors (tobacco use, hypertension, dyslipidemia, diabetes, or renal disease) when compared to patients without risk factors (66.1 vs 5.2 cases/100,000 hospitalizations during pregnancy. Women with gestational diabetes mellitus and preeclampsia also were more likely to have AMI than women without those diagnoses (39.6 vs 7.7 and 21.0 vs. 7.5 cases/100,000 hospitalizations during pregnancy, respectively).
The study had several limitations. The trimester of pregnancy could not be determined from the data set, detailed findings from coronary angiography were not available, and in-hospital medical management was not recorded. The data also may have reflected undercoding and miscoding, and evolving treatment patterns. In addition, no information was available on fetal and newborn outcomes.
The authors believe that the trends in heart attack risk illustrated by their research point to a need for physicians to properly counsel their pregnant patients about risk factors for heart disease. That is particularly important, they said, for women who are older or who have preexisting CAD risk factors and are considering pregnancy. By working with these patients, physicians can develop a plan to monitor and control risk factors to minimize AMI risk during pregnancy.