Menstruation

Figure showing the progression of the menstrual cycle and the different hormones contributing to it

Menstruation, also known as a period or monthly,[1] is the regular discharge of blood and mucosal tissue (known as menses) from the inner lining of the uterus through the vagina.[2] The first period usually begins between twelve and fifteen years of age, a point in time known as menarche.[1] However, periods may occasionally start as young as eight years old and still be considered normal.[2] The average age of the first period is generally later in the developing world, and earlier in the developed world.[3] The typical length of time between the first day of one period and the first day of the next is 21 to 45 days in young women, and 21 to 31 days in adults (an average of 28 days).[2][3] Bleeding usually lasts around 2 to 7 days.[2] Menstruation stops occurring after menopause, which usually occurs between 45 and 55 years of age.[4] Periods also stop during pregnancy and typically do not resume during the initial months of breastfeeding.[2]

Up to 80% of women report having some symptoms prior to menstruation.[5] Common signs and symptoms include acne, tender breasts, bloating, feeling tired, irritability, and mood changes.[6] These may interfere with normal life, therefore qualifying as premenstrual syndrome, in 20 to 30% of women.[5] In 3 to 8%, symptoms are severe.[5]

A lack of periods, known as amenorrhea, is when periods do not occur by age 15 or have not occurred in 90 days.[2] Other problems with the menstrual cycle include painful periods and abnormal bleeding such as bleeding between periods or heavy bleeding.[2] Menstruation in other animals occur in primates (apes and monkeys).[7][8]

The menstrual cycle occurs due to the rise and fall of hormones.[2] This cycle results in the thickening of the lining of the uterus, and the growth of an egg, (which is required for pregnancy).[2] The egg is released from an ovary around day fourteen in the cycle; the thickened lining of the uterus provides nutrients to an embryo after implantation.[2] If pregnancy does not occur, the lining is released in what is known as menstruation.[2]

Onset and frequency

Diagram illustrating how the uterus lining builds up and breaks down during the menstrual cycle

The first menstrual period occurs after the onset of pubertal growth, and is called menarche. The average age of menarche is 12 to 15.[1][9] However, it may start as early as eight.[2] The average age of the first period is generally later in the developing world, and earlier in the developed world.[3] The average age of menarche has changed little in the United States since the 1950s.[3]

Menstruation is the most visible phase of the menstrual cycle and its beginning is used as the marker between cycles. The first day of menstrual bleeding is the date used for the last menstrual period (LMP). The typical length of time between the first day of one period and the first day of the next is 21 to 45 days in young women, and 21 to 31 days in adults (an average of 28 days).[2][3]

Perimenopause is when fertility in a female declines, and menstruation occurs less regularly in the years leading up to the final menstrual period, when a female stops menstruating completely and is no longer fertile. The medical definition of menopause is one year without a period and typically occurs between 45 and 55 in Western countries.[4][10]:p. 381

During pregnancy and for some time after childbirth, menstruation does not occur. The average length of postpartum amenorrhoea is longer when breastfeeding; this is termed lactational amenorrhoea.

Other Languages
Afrikaans: Menstruasie
Alemannisch: Menstruation
العربية: حيض
aragonés: Menstruación
ܐܪܡܝܐ: ܟܦܣܐ
asturianu: Menstruación
azərbaycanca: Menstruasiya
বাংলা: রজঃস্রাব
беларуская: Менструацыя
беларуская (тарашкевіца)‎: Мэнструацыя
български: Менструация
bosanski: Menstruacija
català: Menstruació
čeština: Menstruace
Cymraeg: Mislif
Deutsch: Menstruation
Ελληνικά: Εμμηνόρροια
emiliàn e rumagnòl: Mestruasiòuṅ
español: Menstruación
Esperanto: Menstruo
euskara: Menstruazio
فارسی: قاعدگی
français: Menstruation
Gaeilge: Míostrú
한국어: 월경
հայերեն: Դաշտան
hrvatski: Mjesečnica
Bahasa Indonesia: Menstruasi
interlingua: Menstruation
Interlingue: Menstruation
íslenska: Blæðingar
italiano: Mestruazione
עברית: וסת
ಕನ್ನಡ: ಮುಟ್ಟು
ქართული: მენსტრუაცია
қазақша: Етеккір
Kiswahili: Hedhi
Кыргызча: Этек кир
Latina: Menstrua
latviešu: Menstruācija
lietuvių: Mėnesinės
മലയാളം: ആർത്തവം
مازِرونی: رگ
Bahasa Melayu: Haid
Mìng-dĕ̤ng-ngṳ̄: Nguŏk-gĭng
မြန်မာဘာသာ: ရာသီလာခြင်း
Nederlands: Menstruatie
नेपाली: महिनावारी
日本語: 月経
norsk nynorsk: Menstruasjon
occitan: Menstruacion
ଓଡ଼ିଆ: ଋତୁସ୍ରାବ
oʻzbekcha/ўзбекча: Hayz
ਪੰਜਾਬੀ: ਮਾਹਵਾਰੀ
پنجابی: ماہواری
Plattdüütsch: Menstruatschoon
polski: Menstruacja
português: Menstruação
română: Menstruație
русский: Менструация
Simple English: Menstruation
slovenčina: Menštruácia
slovenščina: Menstruacija
Soomaaliga: Caado-qabid
کوردی: پۆن
српски / srpski: Менструација
srpskohrvatski / српскохрватски: Menstruacija
Basa Sunda: Kareseban
svenska: Menstruation
Tagalog: Regla
Türkçe: Âdet
українська: Менструація
اردو: حیض
Vahcuengh: Dawzsaeg
Tiếng Việt: Kinh nguyệt
walon: Riveyeures
文言: 月經
Winaray: Regla
吴语: 月经
粵語: 月經
Zazaki: Menstruasyon
中文: 月經