Әйелдердің етеккірінің физиологиясы мен ерекшеліктері

Shedding of the uterine lining
menstruation in humans

Menstruation (also known as a period, among other colloquial terms) is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The menstrual cycle is characterized by the rise and fall of hormones. Menstruation is triggered by falling progesterone levels and is a sign that pregnancy has not occurred. The first period, a point in time known as menarche, usually begins between the ages of 12 and 15. Menstruation starting as young as 8 years would still be considered normal. The average age of the first period is generally later in the developing world, and earlier in the developed world. Bleeding usually lasts around 2 to 7 days. Periods stop during pregnancy and typically do not resume during the initial months of breastfeeding. Up to 80% of women do not experience problems sufficient to disrupt daily functioning either during menstruation or in the days leading up to menstruation. Symptoms in advance of menstruation that do interfere with normal life are called premenstrual syndrome (PMS). Some 20 to 30% of women experience PMS, with 3 to 8% experiencing severe symptoms. These include acne, tender breasts, bloating, feeling tired, irritability, and mood changes. Other symptoms some women experience include painful periods and heavy bleeding during menstruation and abnormal bleeding at any time during the menstrual cycle. However, it may occur as early as eight. The average age of menarche has changed little in the United States since the 1950s. The variability of menstrual cycle lengths is highest for women under 25 years of age and is lowest, that is, most regular, for ages 25 to 39 years. The variability increases slightly for women aged 40 to 44 years. Menopause before age 45 is considered premature in industrialized countries. Like the age of menarche, the age of menopause is largely a result of cultural and biological factors. Illnesses, certain surgeries, or medical treatments may cause menopause to occur earlier than it might have otherwise.

The average volume of menstrual fluid during a monthly menstrual period is with considered typical. Menstrual fluid is the correct name for the flow, although many people prefer to refer to it as menstrual blood. Menstrual fluid is reddish brown, a slightly darker color than venous blood. Many women and girls notice blood clots during menstruation. These appear as clumps of blood that may look like tissue. If there was a miscarriage or a stillbirth, examination under a microscope can confirm if it was endometrial tissue or pregnancy tissue (products of conception) that was shed. Sometimes menstrual clots or shed endometrial tissue is incorrectly thought to indicate an early term miscarriage of an embryo. An enzyme called plasmin – contained in the endometrium – tends to inhibit the blood from clotting. The amount of iron lost in menstrual fluid is relatively small for most women. In one study, premenopausal women who exhibited symptoms of iron deficiency were given endoscopies. 86% of them actually had gastrointestinal disease and were at risk of being misdiagnosed simply because they were menstruating. Heavy menstrual bleeding, occurring monthly, can result in anemia.

In most women, various physical changes are brought about by fluctuations in hormone levels during the menstrual cycle. This includes muscle contractions of the uterus (menstrual cramping) that can precede or accompany menstruation. Many women experience painful cramps, also known as dysmenorrhea, during menstruation. Among adult women, that pain is severe enough to affect daily activity in only 2%–28%. These symptoms can be severe enough to affect a person's performance at work, school, and in everyday activities in a small percentage of women. The most common treatment for menstrual cramps are non steroidal anti inflammatory drugs (NSAIDs). NSAIDs can be used to reduce moderate to severe pain, and all appear similar. About 1 in 5 women do not respond to NSAIDs and require alternative therapy, such as simple analgesics or heat pads. Other medications for pain management include aspirin or paracetamol and combined oral contraceptives. Although combined oral contraceptives may be used, there is insufficient evidence for the efficacy of intrauterine progestogens. Another review found insufficient evidence to determine an effect.

Sexual feelings and behaviors change during the menstrual cycle. Before and during ovulation, high levels of estrogen and androgens result in women having a relatively increased interest in sexual activity, and relatively lower interest directly prior to and during menstruation. Unlike other mammals, women may show interest in sexual activity across all days of the menstrual cycle, regardless of fertility. There is no reliable scientific evidence that would advise against sexual intercourse during menstruation based on medical grounds.

Peak fertility (the time with the highest likelihood of pregnancy resulting from sexual intercourse) occurs during just a few days of the cycle: usually two days before and two days after the ovulation date. This corresponds to the second and the beginning of the third week in a 28 day cycle. This fertile window varies from woman to woman, just as the ovulation date often varies from cycle to cycle for the same woman. A variety of methods have been developed to help individual women estimate the relatively fertile and the relatively infertile days in the cycle; these systems are called fertility awareness.

Infrequent or irregular ovulation is called oligoovulation. The absence of ovulation is called anovulation. Normal menstrual flow can occur without ovulation preceding it: an anovulatory cycle. In some cycles, follicular development may start but not be completed; nevertheless, estrogens will be formed and stimulate the uterine lining. Anovulatory flow resulting from a very thick endometrium caused by prolonged, continued high estrogen levels is called estrogen breakthrough bleeding. Anovulatory bleeding triggered by a sudden drop in estrogen levels is called withdrawal bleeding. Anovulatory cycles commonly occur before menopause (perimenopause) and in women with polycystic ovary syndrome. Very little flow (less than 10 ml) is called hypomenorrhea. Regular cycles with intervals of 21 days or fewer are polymenorrhea; frequent but irregular menstruation is known as metrorrhagia. Sudden heavy flows or amounts greater than 80 ml are termed menorrhagia. Heavy menstruation that occurs frequently and irregularly is menometrorrhagia. The term for cycles with intervals exceeding 35 days is oligomenorrhea. Amenorrhea refers to more than three More severe symptoms of anxiety or depression may be signs of premenstrual dysphoric disorder (PMDD) with is a depressive disorder. Dysfunctional uterine bleeding is a hormonally caused bleeding abnormality. Dysfunctional uterine bleeding typically occurs in premenopausal women who do not ovulate normally (i. e. are anovulatory). All these bleeding abnormalities need medical attention; they may indicate hormone imbalances, uterine fibroids, or other problems. As pregnant women may bleed, a pregnancy test forms part of the evaluation of abnormal bleeding. Women who had undergone female genital mutilation (particularly type III infibulation) a practice common in parts of Africa, may experience menstrual problems, such as slow and painful menstruation, that is caused by the near complete sealing off of the vagina.

Menstruation can be delayed by the use of progesterone or progestins. For this purpose, oral administration of progesterone or progestin during cycle day 20 has been found to effectively delay menstruation for at least 20 days, with menstruation starting after 2–3 days have passed since discontinuing the regimen. Hormonal contraception affects the frequency, duration, severity, volume, and regularity of menstruation and menstrual symptoms. The most common form of hormonal contraception is the combined birth control pill, which contains both estrogen and progestogen. Although the primary function of the pill is to prevent pregnancy, it may be used to improve some menstrual symptoms and syndromes which affect menstruation, such as polycystic ovary syndrome (PCOS), endometriosis, adenomyosis, amenorrhea, menstrual cramps, menstrual migraines, menorrhagia (excessive menstrual bleeding), menstruation related or fibroid related anemia and dysmenorrhea (painful menstruation) by creating regularity in menstrual cycles and reducing overall menstrual flow. Using the combined birth control pill, it is also possible for a woman to delay or eliminate menstrual periods, a practice called menstrual suppression. Some women do this simply for convenience in the short term, while others prefer to eliminate periods altogether when possible. This can be done either by skipping the placebo pills, or using an extended cycle combined oral contraceptive pill, which were first marketed in the U. S. in the early 2000s. This continuous administration of active pills without the placebo can lead to the achievement of amenorrhea in 80% of users within 1 year of use.

Breastfeeding causes negative feedback to occur on pulse secretion of gonadotropin releasing hormone (GnRH) and luteinizing hormone (LH). Depending on the strength of the negative feedback, breastfeeding women may experience complete suppression of follicular development, follicular development but no ovulation, or normal menstrual cycles may resume. Suppression of ovulation is more likely when suckling occurs more frequently. The production of prolactin in response to suckling is important to maintaining lactational amenorrhea. On average, women who are fully breastfeeding whose infants suckle frequently experience a return of menstruation at fourteen and a half months postpartum. There is a wide range of response among individual breastfeeding women, however, with some experiencing return of menstruation at two months and others remaining amenorrheic for up to 42 months postpartum.

The word menstruation is etymologically related to moon. The terms menstruation and menses are derived from the Latin mensis , which in turn relates to the ancient Greek mene and to the roots of the English words month and moon. Some organizations have begun to use the term "menstruator" instead of "menstruating women", a term that has been in use since at least 2010. Menstruator is used by activists and scholars in order to "express solidarity with women who do not menstruate, transgender men who do, and intersexual and genderqueer individuals".

Many religions have menstruation related traditions, for example: Islam prohibits sexual contact with women during menstruation in the 2nd chapter of the Quran. Some scholars argue that menstruating women are in a state in which they are unable to maintain wudhu, and are therefore prohibited from touching the Arabic version of the Qur'an. Other biological and involuntary functions such as vomiting, bleeding, sexual intercourse, and going to the bathroom also invalidate one's wudhu. In Judaism, a woman during menstruation is called Niddah and may be banned from certain actions. For example, the Jewish Torah prohibits sexual intercourse with a menstruating woman. In Hinduism, menstruating women are traditionally considered ritually impure and given rules to follow. Menstruation education is frequently taught in combination with sex education at school in Western countries, although girls may prefer their mothers to be the primary source of information about menstruation and puberty. Information about menstruation is often shared among friends and peers, which may promote a more positive outlook on puberty. The quality of menstrual education in a society determines the accuracy of people's understanding of the process. In many Western countries where menstruation is a taboo subject, girls tend to conceal the fact that they may be menstruating and struggle to ensure that they give no sign of menstruation. Programs led by peers or third party agencies are another option.

In some cultures, women were isolated during menstruation due to menstrual taboos. This is because they are seen as unclean, dangerous, or bringing bad luck to those who encounter them. These practices are common in parts of South Asia including India. A 1983 report found women refraining from household chore during this period in India. Chhaupadi is a social practice that occurs in the western part of Nepal for Hindu women, which prohibits a woman from participating in everyday activities during menstruation. Women are considered impure during this time and are kept out of the house and have to live in a shed. Although chhaupadi was outlawed by the Supreme Court of Nepal in 2005, the tradition is slow to change. Women and girls in cultures which practice such seclusion are often confined to menstruation huts, which are places of isolation used by cultures with strong menstrual taboos. The practice has recently come under fire due to related fatalities. Nepal criminalized the practice in 2017 after deaths were reported after the elongated isolation periods, but "the practice of isolating menstruating women and girls continues." Not all cultures villainize menstruation, the Beng people of West Africa consider menstrual blood as sacred and recognize its significance in reproduction.

Even though the average length of the human menstrual cycle is similar to that of the lunar cycle, in modern humans there is no relation between the two. The relationship is believed to be a coincidence. Light exposure does not appear to affect the menstrual cycle in humans. A meta analysis of studies from 1996 showed no correlation between the human menstrual cycle and the lunar cycle, nor did data analyzed by period tracking app Clue, submitted by 1.5million women, of 7.5million menstrual cycles; however, the lunar cycle and the average menstrual cycle were found to be basically equal in length.

Beginning in 1971, some research suggested that menstrual cycles of cohabiting women became synchronized (menstrual synchrony). Subsequent research has called this hypothesis into question. A 2013 review concluded that menstrual synchrony likely does not exist.

Some countries, mainly in Asia, have menstrual leave to provide women with either paid or unpaid leave of absence from their employment while they are menstruating. Countries with policies include Japan, Taiwan, Indonesia, and South Korea. The practice is controversial due to concerns that it bolsters the perception of women as weak, inefficient workers, and that it furthers gender stereotypes and the medicalization of menstruation.