Practice guideline on ovarian tissue cryopreservation and transplantation in the prevention and treatment of iatrogenic premature ovarian insufficiency.

Premature ovarian insufficiency (POI) refers to the decline of ovarian function before the age of 40. POI causes a reduction in or loss of female fertility, accompanied by different degrees of menopausal symptoms, which increases the risk of chronic diseases related to early menopause and seriously affects patients' quality of life and health. It is conservatively estimated that at least one million prepubertal girls and women of reproductive age in China are at risk of iatrogenic POI caused by radiotherapy and chemotherapy every year.