Premature ovarian insufficiency - aetiopathology, epidemiology, and diagnostic evaluation.

Premature ovarian insufficiency (POI) is defined as a cessation of ovarian function before the age of 40 years. It is associated with hypoestrogenism and loss of residual follicles, both of which lead to menstrual abnormalities, pregnancy failures, and decreased health-related quality of life. The prevalence of POI is estimated at 1% in the general population. Current European Society of Human Reproduction and Embryology (ESHRE) diagnostic criteria include: amenorrhoea or oligomenorrhoea for at least four months and increased follicle-stimulating hormone (FSH) levels > 25 IU/l measured twice (with a four-week interval). The aetiopathogenesis of the disease in most cases remains unexplained. Nevertheless, in some patients with POI, genetic abnormalities, metabolic disorders, autoimmunity, iatrogenic procedures, infections, or environmental factors have been established as underlying causes of the syndrome.