<unk>  can be induced or occur naturally. Induced<unk>  occurs as a result of medical treatment such as chemotherapy, radiotherapy, oophorectomy, or complications of tubal ligation, hysterectomy, unilateral or bilateral salpingo-oophorectomy or leuprorelin usage. Age<unk>  typically occurs between 48 and 52 years of age. According to various data, more than 85% of women have their last period between the ages of 46-54 (median 49). 2% of women under the age of 40, 5% between the ages of 40-45 and the same number between the ages of 55-58 have their last bleeding. The average age of the last period in the United States is 51 years, in Russia is 50 years, in Greece is 49 years, in Turkey is 48 years, in Egypt is 47 years and in India is 46 years. The<unk> l transition or perimenopause leading up to<unk>  usually lasts 7 years (sometimes as long as 14 years). In rare cases, a woman's ovaries stop working at a very early age, ranging anywhere from the age of puberty to age 40. This is known as premature ovarian failure and affects 1 to 2% of women by age 40. Undiagnosed and untreated coeliac disease is a risk factor for early<unk> . Coeliac disease can present with several non-gastrointestinal symptoms, in the absence of gastrointestinal symptoms, and most cases escape timely recognition and go undiagnosed, leading to a risk of long-term complications. A strict gluten-free diet reduces the risk. Women with early diagnosis and treatment of coeliac disease present a normal duration of fertile life span. Women who have undergone hysterectomy with ovary conservation go through<unk>  on average 3.7 years earlier than the expected age. Other factors that can promote an earlier onset of<unk>  (usually 1 to 3 years early) are smoking cigarettes or being extremely thin. Premature ovarian failure Premature ovarian failure (POF) is when the ovaries stop functioning before the age of 40 years. It is diagnosed or confirmed by high blood levels of follicle stimulating hormone (FSH) and luteinizing hormone (LH) on at least three occasions at least four weeks apart. Known causes of premature ovarian failure include autoimmune disorders, thyroid disease, diabetes mellitus, chemotherapy, being a carrier of the fragile X syndrome gene, and radiotherapy. However, in about 50–80% of spontaneous cases of premature ovarian failure, the cause is unknown, i.e., it is generally idiopathic. Women who have a functional disorder affecting the reproductive system (e.g., endometriosis, polycystic ovary syndrome, cancer of the reproductive organs) can go into<unk>  at a younger age than the normal timeframe. The functional disorders often significantly speed up the<unk> l process. An early<unk>  can be related to cigarette smoking, higher body mass index, racial and ethnic factors, illnesses, and the surgical removal of the ovaries, with or without the removal of the uterus. Rates of premature<unk>  have been found to be significantly higher in fraternal and identical twins; approximately 5% of twins reach<unk>  before the age of 40. The reasons for this are not completely understood. Transplants of ovarian tissue between identical twins have been successful in restoring fertility. Surgical<unk> <unk>  can be surgically induced by bilateral oophorectomy (removal of ovaries), which is often, but not always, done in conjunction with removal of the Fallopian tubes (salpingo-oophorectomy) and uterus (hysterectomy). Cessation of menses as a result of removal of the ovaries is called "surgical<unk> ". Surgical treatments, such as the removal of ovaries, might cause periods to stop altogether. The sudden and complete drop in hormone levels usually produces extreme withdrawal symptoms such as hot flashes, etc. The symptoms of early<unk>  may be more severe. Removal of the uterus without removal of the ovaries does not directly cause<unk> , although pelvic surgery of this type can often precipitate a somewhat earlier<unk> , perhaps because of a compromised blood supply to the ovaries. The time between surgery and possible early<unk>  is due to the fact that ovaries are still producing hormones.
Menopause
Somatopause
Adrenopause
Menstruation
Premenstrual syndrome
Lactational amenorrhea
Menarche
Pregnancy