Endometrium 6mm, i.e. under the ultrasound probe, it shows that the thickness of the endometrium is 6mm, which can be categorized as normal, thin or thick depending on the different periods of menstruation. Normally, if it is on the 5th to 9th day of the menstrual cycle, the thickness of the endometrium is 6mm, which is within the normal range; on the 10th to 14th day of the menstrual cycle, the endometrium is 6mm thick, which is a bit on the thin side. If it occurs on the 15th to 28th day of the menstrual cycle, although it is normal, the physiological state of the uterus is not conducive to the fertilization of the egg, and the probability of pregnancy will be reduced. Therefore, the significance of an endometrial thickness of 6mm is different at different stages of the menstrual cycle, and it is recommended that it be interpreted under the guidance of a doctor, and that any abnormalities be dealt with promptly.