Thin uterine wall generally refers to the thin lining of the uterus, which can affect fertility. It is recommended to consult an obstetrician and gynecologist in time to clarify the cause of the disease and take appropriate measures. The thickness of the normal endometrium is affected by the menstrual cycle and changes cyclically under the action of estrogen and progesterone secreted by the ovaries. The endometrium in the proliferative phase is usually around 3.8mm, and that in the secretory phase is usually around 8-10mm. Causes of thin endometrium include endometrial injury, endometrial disease or low proliferation, and multiple purges and abortions. Its common effects include menstrual changes, such as reduced menstrual flow, or amenorrhea caused by adhesions in the uterine cavity. Secondly, in terms of fertility, thin endometrium easily affects the fertilized egg’s implantation, which can interfere with normal conception, and even if a normal pregnancy can be achieved, it is prone to miscarriage, thus affecting the reproductive function. Through treatment, if menstruation returns to normal, the effect on fertility is usually small. If adhesions persist, menstruation is very infrequent and does not improve after symptomatic treatment with medication, infertility may result. For endometrial thinning, targeted treatment should be actively pursued, and some patients need to resort to other departmental examinations for a clear diagnosis.