Premature ovarian insufficiency UMLS:C0025322 Hypergonadotropic amenorrhea Climacterium praecox Primary ovarian insufficiency HP:0100805 Premature ovarian failure Premature menopause Menopause praecox Early menopause Amenorrhea due to loss of ovarian function before the age of 40. Primary ovarian insuficiency (POI) is a state of female hypergonadotropic hypogonadism. It can manifest as primary amenorrhea with onset before menarche or secondary amenorrhea. SNOMEDCT_US:373717006 HP:0008209 The causes of primary ovarian insufficiency (POI) include chromosomal and genetic defects, autoimmune processes, chemotherapy, radiation, infections and surgery, but many are unidentified (idiopathic). The age of 40 is set by convention but is supported by clinical observations. From a statistical point of view, the age limit of 40 is approximately two standard deviations (SD) below the average age at natural menopause (50 plus/minus 4 years). UMLS:C0085215 HP:0001587 Abnormal ovarian physiology