Bleeding after 5 days of intercourse is not necessarily caused by a fertilized egg. Bleeding from implantation often refers to red or pink vaginal bleeding in a few women after the fertilized egg has been implanted. Most of the symptoms of bleeding from implantation appear 6-7 days after intercourse, and a few may appear on the fifth day. However, bleeding after 5 days of intercourse may also be caused by luteal insufficiency, ovulatory bleeding, irregular uterine bleeding, etc.: 1. Luteal insufficiency: If a woman has luteal insufficiency, which causes abnormal hormone secretion, it will easily lead to a small amount of red vaginal discharge, which, if preceded by intercourse, is manifested as bleeding after 5 days of intercourse. It is recommended to give hormone supplementation treatment or use drugs to stimulate the corpus luteum, commonly used drugs such as clomiphene. 2. Ovulation bleeding: Due to the short-lived decrease of estrogen level in women’s body during ovulation, the endometrium loses the support of estrogen and may appear to shed and cause regular vaginal bleeding. If 5 days after intercourse happens to be close to ovulation, it may be ovulatory bleeding. Usually the bleeding is not much and not long and does not need special treatment; 3. Irregular uterine bleeding: This condition is not related to whether or not there is implantation. In addition to normal menstrual bleeding, irregular bleeding and contact bleeding may occur, and it may happen that the bleeding occurs 5 days after intercourse, which is manifested as bleeding after 5 days of intercourse. Patients mostly have pelvic tumors, dysfunctional uterine bleeding and other cervical uterine pathologies, etc. A clear diagnosis is needed through gynecological examination and imaging.