Perineal lacerations are divided into three degrees. Among them, the first and second degree perineal lacerations are relatively superficial, with less bleeding. After being properly sutured, most of them heal well. The third degree perineal laceration, or complete perineal laceration, includes vaginal opening lacerations, perineal lacerations, and anal sphincter lacerations. In severe cases, the rupture can extend to the rectal wall, causing fecal and gas incontinence. The cause of the occurrence is mostly due to improper handling during delivery, and occasionally trauma. Due to the vigorous promotion of the new method of delivery, midwives properly protect the perineum, which greatly reduces the incidence of third degree perineal lacerations. It also occasionally occurs in large hospitals in cities.