Menstruation after curettage is rare because the endometrium is injured during the curettage process, causing the endometrium to become thinner, which leads to reduced menstruation. Scraping, also known as abortion, is a process in which a suction tube is placed into the uterus using negative pressure to draw out the pregnancy capsule from the uterine cavity and to clean out the uterine meconium from the uterine cavity. If the pressure is too high or the scraping time is too long, the endometrium may be damaged, which may lead to reduced menstruation. The endometrium is divided into a functional layer and a basal layer, and the functional layer is the one that has cyclic changes of proliferation, secretion and exfoliation, and scraping is the one that may harm the functional layer of the endometrium. Ultrasound can be used to monitor the proliferation of the endometrium after the reduction of menstruation after curettage. If the endometrium does not proliferate well and is relatively thin, medication can be used to promote the growth of the endometrium, most of which are chosen to contain estrogen.