Bleeding on the second day of artificial insemination may be caused by damage to the mucous membrane of the cervical canal or fluctuations in hormone levels, which need to be analyzed specifically. 1. Damage to the mucous membrane of the cervical canal: during artificial insemination, the processed semen will be delivered to the woman’s uterine cavity through a very thin and soft insemination tube, and the process of semen delivery may cause damage to the mucous membrane of the cervix, which will lead to bleeding. 2. Fluctuating hormone levels: Due to fluctuating hormone levels, a small amount of the endometrium is stripped off, resulting in the symptom of bleeding. There may be other reasons for bleeding on the second day of artificial insemination. It is recommended to go to the hospital for relevant examinations in time when this situation occurs, and standardize the treatment under the guidance of the doctor.