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Menstruation
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Menstruation is the result of complex hormonal interactions. During the typical menstrual cycle, the ovaries produce estrogen and progesterone, which cause ovulation to occur and the lining of the uterus (endometrium) to build up. If sexual intercourse takes place and a sperm fertilizes the egg (ovum) as it moves through the fallopian tube, the fertilized egg will implant itself in the endometrium and begin developing into a fetus. If no fertilized egg has implanted itself in the endometrium, the secretion of progesterone from the ovaries declines, which causes the endometrium to be sloughed off. Menstruation usually occurs two weeks after ovulation, although irregular periods are common in early adolescence, and menstruation often takes place without ovulation (anovulatory menstrual bleeding). For many girls, it takes a year or two to establish a predictable menstrual pattern.
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Menstruation is the culmination of a complex series of hormonal events associated with the cyclical production of a mature egg within the ovary and the release of this egg for fertilization. In the first half of the menstrual cycle, ovarian follicles, containing an egg, develop, and produce increasing amounts of oestrogen. This sex hormone stimulates a build-up of the lining of the womb and the growth of spiral arteries into this thickened lining. After ovulation, which occurs around day 14 of the cycle, the empty follicle in the ovary becomes a corpus luteum. This produces high concentrations of progesterone and some oestrogen. The progesterone further increases the thickness of the uterine lining and causes it to secrete a fluid which will nourish a fertilized egg and encourage implantation of the embryo.
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Menstruation has strict cycles of proper procedure. In the first week of the month, the men must reflect on the previous menstruation. In the second week, they are given time to relax without having to give thought to menstruation in any way. In the third week, government pages inform them of what will be discussed in the next week during the menstruation session, or "period" as it is commonly called. The final week is the period, in which all the menstruaters meet together in a conference room to deliberate. They remain in this conference room for the entire week.
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Menstruation forms a normal part of a natural cyclic process occurring in healthy women between puberty and end of the reproductive years. The onset of menstruation, known as menarche, occurs at an average age of 12, but can occur any time between the ages of 8 and 16. The last period, menopause, usually occurs between the ages of 45 and 55. Deviations from this pattern deserve medical attention. Amenorrhea refers to a prolonged absence of menses during the reproductive years of a woman for reasons other than pregnancy. For example, women with very low body fat, such as athletes, may cease to menstruate.
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Menstruation occurs when one of the eggs in the ovaries is released. The egg travels down the fallopian tube towards the uterus. Once the egg is released, estrogen encourages the uterus to build up a thick lining to prepare for pregnancy. If sperm from a male fertilizes the egg, the egg implants itself into the uterine wall and begins to grow a fetus.
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Menstruation usually begins when a girl is about 12 or 13 years old (puberty) and continues until menopause. These are considered a woman’s reproductive years and indicate the woman is physically able to become pregnant. Menstrual periods usually occur once a month and last for several days during each month. A missed menstrual period is frequently the first sign that pregnancy has occurred. The uterine lining is not shed, but rather will grow during pregnancy and develop into the placenta (a temporary organ that provides nourishment for the developing embryo). Missed periods may ... indicate the presence of other gynecological conditions, such as hormonal or endocrine disorders.
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Menstruation