Bleeding during intercourse after IUD is an abnormal phenomenon and is commonly caused by the following reasons: 1. The IUD is ectopic, the stimulation of intercourse by external force causes the uterus to contract, the ectopic IUD will cause the uterine mucosa or cervical mucosa to break and bleed, it is recommended to check the position of the IUD at the hospital in time, if there is any abnormality, replace the IUD with a new one in time. 2. The position of the IUD is normal, but vaginal bleeding during intercourse is often contact bleeding due to local lesions of the cervix. This condition is commonly seen in the early stage of cervical cancer, so it is recommended to do cervical cancer screening to find out whether there are lesions in the cervical epithelium.