Chest pain during pregnancy is defined as chest pain with clinical manifestation of anterior heart area pain or angina pectoris during pregnancy. It is caused by gestational myocardial infarction. Myocardial infarction of pregnancy is a rare complication of pregnancy. It is rarely reported in China. This type of myocardial infarction differs from other types of myocardial infarction because it not only endangers the life of the pregnant woman, but also poses a threat to the fetus. The pathological changes of myocardial infarction in pregnancy are still dominated by coronary artery occlusion, which mostly occurs on the basis of coronary artery atherosclerosis. There are four important findings regarding the pathology of sudden cardiac death: (1) a large proportion of sudden deaths in women are not due to atherosclerotic heart disease; (2) the degree of coronary artery stenosis in women who die suddenly is similar to that in men; (3) the degree of atherosclerosis in women who die from other causes is less severe compared to men of the same age; and (4) the chance of acute pathological changes such as thrombosis occurring is similar in both sexes. The main pathological changes of myocardial infarction in pregnancy are as follows. 1. severity of coronary atherosclerosis. 2, Acute pathological changes in coronary vessels (including thrombosis, coronary thromboembolism, intraplaque hemorrhage). 3, coronary vasospasm. 4, myocardial pathological changes (ischemia, injury, necrosis). 5, Cardiac hypertrophy. 6, Pathological changes of myocardial infarction due to non-coronary atherosclerotic diseases. It is worth mentioning that angiographic coronary arteries may be normal in patients with myocardial infarction in pregnancy, and in the last 10 years, many data have sufficient evidence that the pathological mechanism in patients with such disease is due to coronary artery spasm. Clinical administration of ergometrine to such patients can often induce coronary artery spasm and reproduce the clinical manifestations of myocardial infarction. The name of this condition is confusing in many literatures, thus some call it syndrome X, coronary artery spasm (CAS), variant angina pectoris, vasospastic heart syndrome, angina pectoris syndrome, etc. However, myocardial infarction in pregnancy is definitely different from it, except that it may be etiologically and pathologically the same cause of coronary artery spasm. According to foreign reports, coronary angiograms are often normal in patients with myocardial infarction complicated by pregnancy. It is speculated that this may be due to a decrease in coronary blood flow due to spasm or local thrombosis. The cause of spasm is unclear, and it is considered that it may be related to pregnancy complicated by hypertension, or the use of drugs such as oxytocin. There is also a common cause of coronary artery entrapment separation during pregnancy or in the postpartum period.