ABSTRACT: OBJECTIVE:To analyze trends in the incidence, in-hospital management, and outcomes of acute myocardial infarction (AMI) complicating pregnancy and the puerperium in the United States. PATIENTS AND METHODS:Women 18 years or older hospitalized during pregnancy and the puerperium were identified from the National Inpatient Sample database from January 1, 2002, to December 31, 2014. International Classification of Diseases, Ninth Revision diagnosis and procedure codes were used to identify AMI during pregnancy-related admissions. RESULTS:Overall, 55,402,290 pregnancy-related hospitalizations were identified. A total of 4471 cases of AMI (8.1 [95% CI, 7.5-8.6] cases per 100,000 hospitalizations) occurred, with 922 AMI cases (20.6%) identified in the antepartum period, 1061 (23.7%) during labor and delivery, and 2390 (53.5%) in the postpartum period. ST-segment elevation myocardial infarction occurred in 1895 cases (42.4%), and non-ST-segment elevation myocardial infarction occurred in 2576 cases (57.6%). Among patients with pregnancy-related AMI, 2373 (53.1%) underwent invasive management and 1120 (25.1%) underwent coronary revascularization. In-hospital mortality was significantly higher in patients with AMI than in those without AMI during pregnancy (adjusted odds ratio, 39.9; 95% CI, 23.3-68.4; P<.001). The rate of AMI during pregnancy and the puerperium increased over time (adjusted odds ratio, 1.25 [for 2014 vs 2002]; 95% CI, 1.02-1.52). CONCLUSION:In patients hospitalized during pregnancy and the puerperium, AMI occurred in 1 of every 12,400 hospitalizations and rates of AMI increased over time. Maternal mortality rates were high. Additional research on the prevention and optimal management of AMI during pregnancy is necessary.