The menopausal transition or perimenopause leading up to menopause usually lasts 3–4 years (sometimes as long as 5–14 years).In rare cases, a womans 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 menopause. 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 menopause on average 1.5 years earlier than the expected age. Other factors that can promote an earlier onset of menopause (usually 1 to 3 years early) are smoking cigarettes. Premature ovarian insufficiency
Premature ovarian insufficiency (POI) 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.Premature ovarian insufficiency may be auto immune and therefore co occur with other autoimmune disorders such as thyroid disease, [adrenal insufficiency], and diabetes mellitus. Other causes include chemotherapy, being a carrier of the fragile X syndrome gene, and radiotherapy.
This occurs because a female will stay with her father in her birth community throughout life, initially being closely related to the males and females. Females are born and stay in the group, so relatedness to the females stays about the same. However, throughout time, the older male relatives will die and any sons she gives birth to will disperse, so that local relatedness to males, and therefore the whole group, declines. The situation is reversed in species where males are philopatric and either females disperse, or mating is non-local. Under these conditions, a females reproductive life begins away from her father and paternal relatives because she was either born into a new group from non-local mating or because she dispersed. In the case of female-biased dispersal, the female is initially equally unrelated with every individual in the group, and with non-local mating, the female is closely related to the females of the group, but not the males since her paternal relatives are in another group. As she gives birth, her sons will stay with her, increasing her relatedness to males in the group over time and thus her relatedness with the overall group. The common feature that connects these two otherwise different behaviors is male-biased philopatry, which leads to an increase in kin selection with female age. While not conclusive, evidence does exist to support the idea that female-biased dispersal existed in pre-modern humans. The closest living relatives to humans, chimpanzees, bonobos, and both mountain gorillas and western lowland gorillas, are female-biased dispersers.