The depth of a woman’s uterine cavity is usually 5~9cm, if it is less than 5cm, it means that the uterine cavity is too small, and if it is more than 9cm, it means that the uterine cavity is enlarged. 1. Small uterine cavity: the depth of the uterine cavity is less than 5cm may be congenital uterine dysplasia, small uterine cavity can also be seen in the breastfeeding period, this situation will usually return to normal, after the menopause, the uterus atrophy, and thus the uterus is also too small. 2. Enlargement of the uterine cavity: a uterus larger than 9cm can be seen after childbirth, both after normal delivery and cesarean section, which usually returns to normal, and poor uterine regeneration after delivery can also lead to an enlarged uterus. In addition, uterine fibroids, adenomyosis, etc. can also cause enlargement of the uterus. There may be many other reasons for uterine cavity enlargement, so it is recommended to consult a doctor in time to clarify the cause and have the doctor formulate an individualized diagnosis and treatment plan according to the specific condition, so as to avoid delaying the condition.