Centered uterine cavity waves, uneven endometrial echogenicity, and a 7 mm thick endometrium may be caused by endometrium in secretory phase, endometrial polyps, and submucosal fibroids. 1. secretory endometrium: the endometrium will change significantly with the menstrual cycle, in the secretory phase of the menstrual cycle, the endometrium gradually thickened, the endometrium is more rich in blood vessels, which may cause the uterine cavity wave centered, the endometrium echogenicity is uneven, the endometrium is 7 mm thick, which may be a normal performance. 2. Endometrial polyps: If the female patient has endometrial polyps, the endometrium is uneven, which may cause uneven endometrial echogenicity, and the thickness of the endometrium reaches 7 millimeters, the uterine cavity wave may be centered. 3. Submucosal fibroids: female patients with submucosal fibroids, may cause endometrial irregularities, ultrasound can be seen endometrial echogenicity is not uniform, there may be endometrial thickness of 7mm, the cavity wave is centered. A centered uterine wave, uneven endometrial echogenicity, and a 7 mm thick endometrium need to be diagnosed and treated under the guidance of an obstetrician and gynecologist, depending on the condition of the patient.