Redness on straining in mid-pregnancy may be caused by hemorrhoids, placenta hypoplasia, and preeclampsia. 1. Hemorrhoids: after pregnancy, the increased uterine compression and increased abdominal pressure will cause hemorrhoidal venous reflux obstruction and increased pressure, may aggravate hemorrhoids, manifested as bleeding when straining, mostly fresh blood, accompanied by pain, may be recurrent, combined with the history and physical examination to clarify the diagnosis. 2. Placenta hypoplasia: when ultrasound examination during pregnancy suggests that the position of the placenta is low, or reaches the endocervical os, the symptom of vaginal bleeding may also occur when straining to increase the abdominal pressure, not accompanied by abdominal pain. Combined with history and ultrasound examination, the diagnosis is clear. 3. Pre-eclampsia: mainly manifested by vaginal bleeding and paroxysmal abdominal pain and other symptoms, may also bleed when straining, ultrasound examination of fetal development is normal, combined with the history and clinical manifestations can assist in the diagnosis. When the mid-pregnancy when the stool on exertion see red need to go to the hospital, in order to identify the cause, and actively deal with.