A little bit of blood in the womb the day after menstruation can be attributed to the fact that menstruation is not completely finished, and it can also be caused by cervicitis, fibroids and other diseases. 1. the menstrual period is not completely finished: if the menstrual period is not completely finished, there will be a phenomenon of return, may cause the menstrual period the next day to have a little blood. 2. Cervicitis: The cause of cervicitis is mainly due to infection of the uterus by pathogens such as Chlamydia trachomatis and Neisseria gonorrhoeae, and disorders of vaginal flora and hormonal imbalance may also lead to disease. Typical symptoms are small amount of bleeding after sexual intercourse or extra bleeding between menstrual periods. 3. Uterine fibroids: the cause of uterine fibroids is not yet clear, may be related to genetics, sex hormone level imbalance and other factors, the clinical manifestations of irregular vaginal bleeding during non-menstrual period, some patients may bleed the day after menstruation coitus. There are many reasons for a little bleeding during intercourse on the second day after menstruation, and it is recommended that the patient should consult a doctor in time to clarify the cause of the disease.