Vaginal bleeding after pregnancy is not menstruation in the real sense, but abnormal vaginal bleeding, which is mainly seen in the following three cases. First, abnormal bleeding caused by preeclampsia, which is mainly due to maternal factors, paternal factors or other factors, resulting in abnormal development of the embryo, which leads to bleeding. Patients need to check the blood chorionic gonadotropin and progesterone to observe the development of the gestational sac, and if necessary, to preserve the fetus. If the development is not good and stops developing, then the uterus needs to be cleared. Second, consider ectopic pregnancy, ectopic pregnancy caused by bleeding is mainly due to the low activity of the gestational sac, the endometrium lost hormone levels to support and lead to. So in this case, the patient needs to dynamically observe the changes in blood chorionic gonadotropin and ultrasound, and choose drugs for conservative or embryonic killing treatment. Third, consider the cervical or vaginal bleeding, this situation needs to do gynecological internal examination, observe the bleeding site, find the cause of bleeding.