Thin uterus refers to the thin endometrium, and the clinical consequences are: firstly, the menstrual flow will be significantly reduced. Secondly, it can cause infertility in clinical practice. To find out the causes of thin endometrium, the most common is endocrine disorder and decrease in estrogen level, resulting in thin endometrium, it is recommended to supplement estrogen, which can improve the thickness of endometrium. It is possible that oral administration of short-acting contraceptives has caused the endometrium to atrophy, resulting in thinning of the endometrium. After stopping the short-acting contraceptives, the endometrium will be restored to its original thickness. A history of hysterectomy, which causes incomplete adhesions in the uterine cavity and results in a thin endometrium, requires hysteroscopy to separate the adhesions and improve the thin endometrium.