Bleeding in the second trimester of pregnancy can be caused by pre-eclampsia, ectopic pregnancy, gravida, combined cervical lesions of pregnancy and external irritation. If a pregnant woman has had a previous hospital visit to confirm intrauterine pregnancy (the embryo is located in the uterus) and has irregular small amount of vaginal bleeding in the second trimester without abdominal pain or vague abdominal pain, there is a possibility of pre-eclampsia miscarriage and she should seek medical attention promptly. If there is no abnormality in the gynecological examination of the cervix, bleeding from cervical lesions can be excluded and preterm abortion is mainly considered. If there are no obvious external factors (external impact on the abdomen, intercourse, etc.), consider bleeding due to insufficient hormone levels (HCG or progesterone) in the body to maintain the nutritional demand of the endometrium for embryonic development. In this case, the blood HCG and progesterone levels should be rechecked and the early pregnancy ultrasound should be repeated. If the ultrasound indicates normal embryonic development, but the trend of blood hormone level growth is unsatisfactory, the pregnant woman should rest in bed and take oral fetal preservation drugs; if there is no relief, breech intramuscular injection of progesterone type drugs can be used for fetal preservation treatment; if the ultrasound indicates fetal arrest and the blood hormone level decreases significantly compared with the previous one, the patient is considered to have embryonic arrest and needs to undergo clearance as soon as possible. If there is no clear intrauterine early pregnancy in the past, only positive urine test paper at home, bleeding in the second month of pregnancy does not exclude the possibility of ectopic pregnancy, you should consult a hospital promptly for clarification, if accompanied by obvious abdominal pain, you should consult a nearby hospital immediately. Blood HCG and vaginal ultrasound should be checked and if the result shows ectopic pregnancy, appropriate treatment is needed. If, in addition to vaginal bleeding, the uterus is abnormally enlarged and soft, and the pregnancy vomiting is early and severe, or even combined with hypertension and edema, you should be alerted to the possibility of gravidity, and after the diagnosis is clear, the uterus should be removed immediately. In conclusion, in the second month of pregnancy, regardless of the cause of bleeding, prompt medical attention is needed, especially for pregnant women with undetermined intrauterine pregnancy, who need to be alert to bleeding caused by ectopic pregnancy.