Menstrual period usually refers to menstruation. It is normal if menstruation is delayed for about one month after the abortion. If menstruation still does not occur three months after the abortion, or the amount of menstruation is too small, it is considered to be caused by the damage of the endometrial basal layer or the adhesion of the uterine cavity, and so on. 1. Normal phenomenon: women may experience delayed menstruation or decreased menstrual flow after abortion, usually the situation improves three months after abortion, which is caused by the damage to the endometrium caused by abortion surgery. 2. Damage to the basal layer of the endometrium: the endometrium is divided into the functional layer and the basal layer, and the functional layer has the ability to regenerate. If the basal layer of the endometrium is damaged during the abortion surgery, there will be no menstruation or delayed menstruation. 3. Uterine adhesion: Uterine adhesion is a variety of factors lead to endometrial damage and make the uterine cavity occlusion, commonly invasive operation of the uterine cavity, the patient will have a decrease in menstruation, amenorrhea and other symptoms. There are more reasons for not having menstruation after abortion, so it is recommended that patients go to the hospital and undergo relevant examinations.