Pregnancy-Related Acute Myocardial Infarction in Japan

BACKGROUND: Pregnancy-related acute myocardial infarction (AMI) is uncommon, but can result in maternal and/or fetal death. This study retrospectively reviews pregnancy-related AMI reported from medical institutions in Japan. METHODS AND RESULTS: We electronically or manually searched the literature for reports of pregnancy-related AMI between 1981 and 2011. In total, 62 patients were described and the numbers increased in accordance with the rising average age of the mothers. AMI occurred frequently in women aged 30-34 years (mean age, 33), in the third trimester and postpartum (n=11 and n=28, respectively). The prevalence of conventional risk factors was relatively low (n=21). On the other hand, 29 patients had obstetric and/or non-obstetric complications, and 24 received medication. Only 8 AMI were caused by atherosclerosis, while coronary dissection, thrombus and spasm were the cause in 14, 9 and 12 cases, respectively. All patients with atherosclerosis had conventional risk factors, and some patients with spasm had a history of smoking. Medication with ergot derivatives was associated mostly with spasm, whereas ritodrine was potentially related to dissection. CONCLUSIONS: The prevalence of pregnancy-related AMI in Japan seems lower than in Western countries, and the etiology differs considerably. However, as the trend of later childbearing continues, more pregnant women have more risk factors, complications, and require medication. Cardiologists and obstetricians must consider the increased risk of AMI.