This chapter describes the summary of guidelines on premature menopause, endometriosis and polycystic ovarian disease. Premature ovarian insufficiency (POI) (also known as premature menopause) is defined as primary hypogonadism before the age of 40 years in women with a normal karyotype who previously had normal menstrual cycles. The diagnosis of POI is confirmed by the finding of follicular stimulating hormone (FSH) levels 40 IU/l on two occasions 4–6 weeks apart. In contrast to the treatment of postmenopausal osteopenia or osteoporosis, which focuses on bisphosphonates as first-line therapy, low bone mass in women with primary ovarian insufficiency is managed most appropriately with HT—ACOG. Polycystic ovarian syndrome (PCOS) is the single most common endocrine metabolic disorder of humans, affecting up to 15% of women. It is characterized by chronic oligo- or anovulation, hyperandrogenism, hyperinsulinemia, dyslipidemia, and metabolic syndrome.