menstrual cycle
Sign in to savea type of ovulation cycle where the endometrium is shed if pregnancy does not occur
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The menstrual cycle is a monthly process in which the body prepares for possible pregnancy by building up the uterine lining, and then sheds that lining if pregnancy doesn't happen. This cycle matters because it's a key part of reproductive health and fertility in people with female reproductive systems.
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Article
Menstrual cycle The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that makes pregnancy possible. The ovarian cycle controls the production and release of eggs and the cyclic release of estrogen and progesterone. The uterine cycle governs the preparation and maintenance of the lining of the uterus (womb) to receive an embryo. These cycles are concurrent and coordinated, normally last between 21 and 35 days, with a median length of 28 days. Menarche (the onset of the first period) usually occurs around the age of 12 years; menstrual cycles continue for about 30–45 years.
Naturally occurring hormones drive the cycles; the cyclical rise and fall of the follicle stimulating hormone prompts the production and growth of oocytes (immature egg cells). The hormone estrogen stimulates the uterus lining (endometrium) to thicken to accommodate an embryo should fertilization occur. The blood supply of the thickened lining provides nutrients to a successfully implanted embryo. If implantation does not occur, the lining breaks down and blood is released. Triggered by falling progesterone levels, menstruation (commonly referred to as a "period") is the cyclical shedding of the lining, and is a sign that pregnancy has not occurred.