The thickness of the endometrium changes with the menstrual cycle, and menstruation does not occur until the endometrium reaches about 12 mm. The endometrium is thinnest at the end of menstruation, and the endometrium gradually grows from the follicular phase, and further thickens with the arrival of ovulation, reaching its thickest before menstruation. The thickness of the endometrium is different for each person due to their physical condition. As long as the endometrium thickens to about 10mm, it will not affect the onset of menstruation. If the endometrium is damaged by frequent abortions, the thinning or adhesion of the endometrium can cause delayed menstruation, reduced menstrual flow or even amenorrhea. It is important to pay attention to the maintenance of the uterus, eat more nutritious food and avoid unwanted pregnancy by using contraception during intercourse. If the thickness of the endometrium is abnormal, too thick or too thin, it will affect the fertilization of the egg and there is a great risk of miscarriage even after pregnancy, so medication should be taken in time to regulate it.