The endometrium is an important part of the uterine lining that is sensitive to progesterone and can shed and proliferate with the menstrual cycle. The thickness of the endometrium varies at different times during the menstrual cycle. It is recommended to have a vaginal ultrasound three days after menstruation to find out the exact thickness of the endometrium. The normal endometrial thickness is about 0.2-1.0 cm. If the endometrium is thicker than normal, it may easily lead to menstrual pain or fertilized eggs not easily laid. When the thickness of the endometrium exceeds the normal range, it affects a woman’s pregnancy. Generally, endometrial thickening is associated with endocrine disorders, most patients have relatively abnormal ovulation, and some women with thick endometrium are also polycystic ovaries or anovulatory patients in clinical practice. Moreover, endometrial thickening is prone to symptoms such as menstrual bleeding and prolonged menstrual cycle. The discharge of menstrual blood and bloody leucorrhea increases the chance of bacterial infection, which can easily lead to inflammation of the reproductive tract, and serious diseases can directly affect a woman’s pregnancy. In addition, some patients with endometrial thickening combine with endometrial inflammation, when the patient’s uterine environment is poor and even affects the tolerance of the endometrium, which can easily lead to unstable embryo implantation and the possibility of early pregnancy miscarriage.