In the ovulation period endometrial thickness of 9mm can be pregnant, under normal circumstances, in the ovulation period endometrial thickness of about 8-10mm, this period of dominant follicle has matured, the egg can be discharged at any time, soon after ovulation endometrial gradually thickened about 10-12mm, such endometrial thickness is very suitable for fertilization of the egg to bed. The thickness of the endometrium will change with the physiological cycle of women, in the period of menstruation just clean endometrium is very thin, the thickness of about 3-5mm, follicular endometrium about 6-7mm, ovulation endometrium thickness of about 8-9mm, pre-menstrual endometrium thickness of about 14-16mm, the thickness of the endometrium cycle is regulated by the secretion of hormones, and the ovary cyclic changes The endometrial thickness cycle is regulated by secretory hormones and is inextricably linked to the ovarian cycle.