The normal endometrium of reproductive age is 8~12mm thick during premenstrual period. Thick endometrium is generally considered as the following possible diseases: 1. Endometrial lesion Whether simple hyperplasia, compound hyperplasia or atypical hyperplasia or endometrial malignant lesion; 2. Endometrial polyp; 3. Normal endometrium But the endometrium is thickened because of long-term absence of ovulation and lack of progesterone conversion; 4. Local problem of endometrium. For patients with endometrial thickening, the focus should be on whether there is ovulation. 1. If ovulation is present Vaginal ultrasound is repeated after the end of menstruation to understand the thickness of the endometrium and whether it is uniform. If the endometrium is still thick at this time, hysteroscopy is done if necessary, there may be: ① endometrial polyp, if the patient has no clinical symptoms and the polyp is less than 2 cm, it can be observed; ② endometrium shows polyp-like changes, the patient has ovulation and her menstruation is very normal, it can be observed, or a Manned If there is no ovulation 2, if there is no ovulation No ovulation means no progesterone production, the endometrium is under the action of single estrogen for a long time showing proliferation of endometrium, or hyperplasia has occurred, including simple hyperplasia, compound hyperplasia, atypical hyperplasia. What is lacking is supplemented by regular progestin supplementation to fully convert the endometrium, and for endometrial compound hyperplasia and atypical hyperplasia, high-dose progestin therapy is required.