The causes of vaginal bleeding after defecation are: 1. bleeding after defecation in women in early pregnancy is a sign of pre-eclampsia and is considered to be caused by abnormal embryonic development. 2. placenta praevia, which occurs in pregnant women in the middle and late stages of pregnancy, causes vaginal bleeding after defecation. The symptoms are due to the low position of the placenta, which causes bleeding when the edge of the placenta peels off during defecation. 3.Vaginal bleeding after defecation in non-pregnant women is caused by cervical polyps, cervical cancer, endometrial polyps, endometrial cancer, submucosal fibroids and other gynecological neoplastic diseases, and is caused by blood oozing from the surface of the diseased tissue during defecation.