Risk Factors and Timing of Acute Myocardial Infarction Associated With Pregnancy: Insights From the National Inpatient Sample

BACKGROUND: Pregnancy increases the risk of acute myocardial infarction (AMI). The purpose of this study was to examine timing and risk factors for AMI in pregnancy and poor outcome. METHODS AND RESULTS: National Inpatient Sample (2003–2015) was screened in pregnancy, labor and delivery, and postpartum. There were 11 297 849 records extracted with 913 instances of AMI (0.008%). One hundred eleven (12.2%) women experienced AMI during labor and delivery, 338 (37.0%) during pregnancy and most during the postpartum period (464; 50.8%). The prevalence of AMI in pregnancy has increased (P=0.0005). Most major adverse cardiovascular and cerebrovascular events occurred in the postpartum period (63.5%). Inpatient mortality was 4.5%. Predictors of AMI include known coronary artery disease (odds ratio [OR], 517.4; 95% CI, 420.8–636.2), heart failure (OR, 8.2; 95% CI, 1.9–35.2), prior valve replacement (OR, 6.4; 95% CI, 2.4–17.1), and atrial fibrillation (OR, 2.7; CI, 1.5–4.7; P<0.001). Risk factors of traditional atherosclerosis including hyperlipidemia, obesity, tobacco history, substance abuse, and thrombophilia were identified (P<0.001). Gestational hypertensive disorders (eclampsia OR, 6.0; 95% CI, 3.3–10.8; preeclampsia OR, 3.2; 95% CI, 2.5–4.2) were significant risk factors in predicting AMI. Risk factors associated with major adverse cardiovascular and cerebrovascular events included prior percutaneous coronary intervention (OR, 6.6; 95% CI, 1.4–31.2) and pre‐eclampsia (OR, 2.3; 95% CI, 1.3–3.9). CONCLUSIONS: AMI is associated with modifiable, nonmodifiable, and obstetric risk factors. These risk factors can lead to devastating adverse outcomes and highlight the need for risk factor modification and public health resource initiatives toward the goal of decreasing AMI in the pregnant population.