Postpartum coital bleeding may be caused by poor uterine recovery, cervical polyps, uterine submucosal fibroids and other reasons. 1. Poor post-partum recovery: Since it takes 6 weeks for the uterine lining to be completely repaired after delivery, coitus should be prohibited during the puerperium to avoid infection. When the uterus recovers poorly after delivery or when the soft birth canal is damaged during delivery, vaginal bleeding can be caused by the stimulation of coitus, and the combination of gynecological examination and ultrasonography can assist in the diagnosis. 2. Cervical polyps: can also cause a small amount of vaginal bleeding after coitus, can be repeated, and not accompanied by abdominal pain, gynecological examination can help diagnosis. 3. Uterine submucous fibroids: for the cervix out of the cervix to the vagina of the uterine submucous fibroids, can also cause vaginal bleeding after coitus, can also be accompanied by an increase in vaginal secretion, ultrasound and gynecological examination can assist in the diagnosis. When postpartum coitus bleeding need to go to the hospital in time to identify the cause, and timely treatment.