View source for Menstruation

{{Short description|Periodic shedding of the uterine lining}}
{{About|menstruation in humans|menstruation in other mammals|Menstruation (mammal)}}
{{Pp-vandalism|small=yes}}
{{More medical citations needed|date=February 2021}}
{{Use dmy dates|date=January 2018}}
[[File:Lining of Uterine Wall.jpg|thumb|Diagram illustrating how the [[endometrium|uterine lining]] builds up and breaks down during the menstrual cycle]]
'''Menstruation''' (also known as a '''period''', among other colloquial terms) is the regular discharge of [[blood]] and [[Mucous membrane|mucosal tissue]] from the [[endometrium|inner lining of the uterus]] through the [[vagina]].<ref name=Thiyagarajan>{{cite journal |last1=Thiyagarajan |first1=Dhanalakshmi K. |last2=Basit |first2=Hajira |last3=Jeanmonod |first3=Rebecca |title=Physiology, Menstrual Cycle |journal=StatPearls |date=27 September 2024 |url=https://www.ncbi.nlm.nih.gov/books/NBK500020/ |publisher=StatPearls Publishing|pmid=29763196}}</ref> The [[menstrual cycle]] is characterized by the rise and fall of [[hormones]].<ref name=Thiyagarajan/> Menstruation is triggered by falling [[progesterone]] levels, and is a sign that [[pregnancy]] has not occurred.<ref name=Thiyagarajan/> [[Feminine hygiene]] products are used in order to maintain hygiene during '''menses'''.

The first period, a point in time known as [[menarche]], usually begins during [[puberty]], between the ages of 11 and 13.<ref name="Jones2011">{{cite book|url=https://books.google.com/books?id=pj_ourS3PBMC&pg=PA94|title=Women's Gynecologic Health|date=2011|publisher=Jones & Bartlett Publishers|isbn=978-0-7637-5637-6|page=94|archive-url=https://web.archive.org/web/20150626120253/https://books.google.ca/books?id=pj_ourS3PBMC&pg=PA94|archive-date=26 June 2015|url-status=live}}</ref> However, menstruation starting as young as eight years would still be considered normal.<ref name="Women2014Men">{{cite web|date=23 December 2014|title=Menstruation and the menstrual cycle fact sheet|url=http://www.womenshealth.gov/publications/our-publications/fact-sheet/menstruation.html|archive-url=https://web.archive.org/web/20150626134338/http://www.womenshealth.gov/publications/our-publications/fact-sheet/menstruation.html|archive-date=26 June 2015|access-date=25 June 2015|website=Office of Women's Health}}</ref> The average age of the first period is generally later in the [[developing world]], and earlier in the [[developed world]].<ref name=Diaz2006/> 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; in adults, the range is between 21 and 35 days with the average often cited as 28 days.<ref name="Women2014Men"/><ref name=Diaz2006>{{cite journal | vauthors = Diaz A, Laufer MR, Breech LL | title = Menstruation in girls and adolescents: using the menstrual cycle as a vital sign | journal = Pediatrics | volume = 118 | issue = 5 | pages = 2245–2250 | date = November 2006 | pmid = 17079600 | doi = 10.1542/peds.2006-2481 | s2cid = 37802775 | doi-access =  }}</ref> In the largest study of menstrual app data, the mean menstrual cycle length was determined to be 29.3 days.<ref name=":6">{{cite journal | vauthors = Bull JR, Rowland SP, Scherwitzl EB, Scherwitzl R, Danielsson KG, Harper J | title = Real-world menstrual cycle characteristics of more than 600,000 menstrual cycles | journal = npj Digital Medicine | volume = 2 | issue = 1 | article-number = 83 | date = 2019-08-27 | pmid = 31482137 | pmc = 6710244 | doi = 10.1038/s41746-019-0152-7 }}</ref> Bleeding typically lasts two to seven days. Periods stop during pregnancy and typically do not resume during the initial months of [[breastfeeding]].<ref name="Women2014Men"/> [[Lochia]] occurs after childbirth.<ref>{{cite web |title=Pregnancy: Physical Changes After Delivery |url=https://my.clevelandclinic.org/health/articles/9682-pregnancy-physical-changes-after-delivery |website=Cleveland Clinic |access-date=16 August 2024}}</ref> Menstruation, and with it the possibility of pregnancy, ceases after [[menopause]], which usually occurs between 45 and 55 years of age.<ref name=NIH2013Def>{{cite web|title=Menopause: Overview|url=https://www.nichd.nih.gov/health/topics/menopause|website=National Institutes of Health |access-date=8 March 2015|date=28 June 2013 |archive-url=https://web.archive.org/web/20150402111845/http://www.nichd.nih.gov/health/topics/menopause/Pages/default.aspx|archive-date=2 April 2015|url-status=live}}</ref>

During their menstrual period, 38% of all women reported not to be able to perform all their regular daily activities.<ref name=" The impact of menstrual symptoms on everyday life: a survey among 42,879 women ">{{cite journal | vauthors = Schoep ME, Nieboer TE, van der Zanden M, Braat DD, Nap AW | title = The impact of menstrual symptoms on everyday life: a survey among 42,879 women | journal = Am J Obstet Gynecol | volume = 220 | issue = 6 | date = 2019 | pmid = 30885768 | doi = 10.1016/j.ajog.2019.02.048 | doi-access = free }}</ref> 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.<ref name=AFP2011>{{cite journal | vauthors = Biggs WS, Demuth RH | title = Premenstrual syndrome and premenstrual dysphoric disorder | journal = American Family Physician | volume = 84 | issue = 8 | pages = 918–924 | date = October 2011 | pmid = 22010771 }}</ref> These include [[acne vulgaris|acne]], tender breasts, bloating, feeling tired, irritability, and mood changes.<ref name=Women2014PMS>{{cite web|title=Premenstrual syndrome (PMS) fact sheet|url=http://www.womenshealth.gov/publications/our-publications/fact-sheet/premenstrual-syndrome.html|website=Office on Women's Health|access-date=23 June 2015|date=23 December 2014|archive-url=https://web.archive.org/web/20150628073755/http://www.womenshealth.gov/publications/our-publications/fact-sheet/premenstrual-syndrome.html|archive-date=28 June 2015}}</ref> Other symptoms some women experience include [[dysmenorrhea|painful periods]] (estimates are between 50 and 90%) and heavy bleeding during menstruation and [[abnormal uterine bleeding|abnormal bleeding]] at any time during the menstrual cycle.<ref name="Women2014Men" /> A lack of periods, known as [[amenorrhea]], is when periods do not occur by age 15 or have not re-occurred in ninety days.<ref name=Women2014Men/>{{TOC limit|3}}

== Characteristics ==
{{Further|Menstrual cycle}}

===Length and duration===
The first menstrual period occurs after the onset of pubertal growth, and is called [[menarche]]. The average age of menarche is 12 to 15 years.<ref name="Jones2011"/><ref>{{cite journal | vauthors = Karapanou O, Papadimitriou A | title = Determinants of menarche | journal = Reproductive Biology and Endocrinology | volume = 8 | page = 115 | date = September 2010 | pmid = 20920296 | pmc = 2958977 | doi = 10.1186/1477-7827-8-115 | doi-access = free }}</ref> However, it may occur as early as eight.<ref name="Women2014Men"/> The average age of the first period is generally later in the [[developing world]], and earlier in the [[developed world]].<ref name=Diaz2006/><ref name="pmid29778270">{{cite journal | vauthors = Alvergne A, Högqvist Tabor V | title = Is Female Health Cyclical? Evolutionary Perspectives on Menstruation | journal = Trends in Ecology & Evolution | volume = 33 | issue = 6 | pages = 399–414 | date = June 2018 | pmid = 29778270 | doi = 10.1016/j.tree.2018.03.006 | arxiv = 1704.08590 | bibcode = 2018TEcoE..33..399A | s2cid = 4581833 }}</ref> The average age of menarche has changed little in the United States since the 1950s.<ref name=Diaz2006/>

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 35 days in adults.<ref name="Women2014Men"/><ref name="Diaz2006" /> The average menstrual cycle length is conventionally said to be 28 days.<ref name="Women2014Men"/><ref name=Diaz2006>{{cite journal | vauthors = Diaz A, Laufer MR, Breech LL | title = Menstruation in girls and adolescents: using the menstrual cycle as a vital sign | journal = Pediatrics | volume = 118 | issue = 5 | pages = 2245–2250 | date = November 2006 | pmid = 17079600 | doi = 10.1542/peds.2006-2481 | s2cid = 37802775 | doi-access =  }}</ref> In the largest study using data from menstrual apps, the mean menstrual cycle length was determined as 29.3 days.<ref name=":6">{{cite journal | vauthors = Bull JR, Rowland SP, Scherwitzl EB, Scherwitzl R, Danielsson KG, Harper J | title = Real-world menstrual cycle characteristics of more than 600,000 menstrual cycles | journal = npj Digital Medicine | volume = 2 | issue = 1 | article-number = 83 | date = 2019-08-27 | pmid = 31482137 | pmc = 6710244 | doi = 10.1038/s41746-019-0152-7 }}</ref> 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.<ref name="Chiazze1968">{{cite journal | vauthors = Chiazze L, Brayer FT, Macisco JJ, Parker MP, Duffy BJ | title = The length and variability of the human menstrual cycle | journal = JAMA | volume = 203 | issue = 6 | pages = 377–380 | date = February 1968 | pmid = 5694118 | doi = 10.1001/jama.1968.03140060001001 }}</ref> The variability increases slightly for women aged 40 to 44 years.<ref name="Chiazze1968" />

[[Perimenopause]] refers to the transitional phase leading up to menopause, marked by hormonal changes and irregular menstrual cycles, when a woman 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 years in Western countries.<ref name="NIH2013Def" /><ref name = "Carlson_2004">{{cite book |vauthors= Carlson KJ, Eisenstat SA, Ziporyn TD |title = The new Harvard guide to women's health | year = 2004 | publisher = Harvard University Press | location = Cambridge, Massachusetts | isbn = 0-674-01343-3 | url-access = registration | url = https://archive.org/details/newharvardguidet00carl }}</ref>{{rp|381}} Menopause before age 45 is considered ''premature'' in industrialized countries.<ref>{{cite web|title=Clinical topic&nbsp;— Menopause|url=http://www.cks.nhs.uk/menopause#-292420|archive-url=https://web.archive.org/web/20090707095123/http://www.cks.nhs.uk/menopause#-292420|archive-date=7 July 2009|access-date=2 November 2009|work=NHS}}</ref> Illnesses, certain surgeries, or medical treatments may cause menopause to occur earlier than it might have otherwise.<ref name="pmid31027683">{{cite journal | vauthors = Mishra GD, Chung HF, Cano A, Chedraui P, Goulis DG, Lopes P, Mueck A, Rees M, Senturk LM, Simoncini T, Stevenson JC, Stute P, Tuomikoski P, Lambrinoudaki I | display-authors = 6 | title = EMAS position statement: Predictors of premature and early natural menopause | journal = Maturitas | volume = 123 | issue =  | pages = 82–88 | date = May 2019 | pmid = 31027683 | doi = 10.1016/j.maturitas.2019.03.008 | hdl-access = free | s2cid = 87361924 | hdl = 10138/318039 }}</ref>

===Menstrual fluid===
[[File:Menstrual fluid in cup 2nd day 40s female.jpg|thumb|[[Menstrual cup]] filled with menstrual fluid]]
The average volume of menstrual fluid during a monthly menstrual period is {{convert|35|ml|USfloz|abbr=on}} with {{convert|10|-|80|ml|abbr=on|USfloz}} considered typical. ''Menstrual fluid'' is the correct term 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.<ref name = "Carlson_2004" />{{rp|381}}

About half of menstrual fluid is blood. This blood contains sodium, calcium, phosphate, iron, and chloride, the extent of which depends on the woman. As well as blood, the fluid consists of cervical mucus, vaginal secretions, and [[Endometrium|endometrial tissue]]. Vaginal fluids in menses mainly contribute water, common electrolytes, organ moieties, and at least 14 proteins, including glycoproteins.<ref>{{cite book| vauthors = Farage M |title=The Vulva: Anatomy, Physiology, and Pathology|date=22 Mar 2013|publisher=CRC Press|pages=155–158}}</ref>

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.<ref>{{cite web|title=Menstrual blood problems: Clots, color and thickness|url=http://women.webmd.com/menstrual-blood-problems-clots-color-and-thickness|website=WebMD|access-date=20 September 2011|url-status=live|archive-url=https://web.archive.org/web/20110923151848/http://women.webmd.com/menstrual-blood-problems-clots-color-and-thickness|archive-date=23 September 2011}}</ref> 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 [[blood clotting|clotting]].<ref>{{citation|author=C. J. Dockeray, B. L. Sheppard, L. Daly, J. Bonnar |date=April 1987 |doi=10.1016/0028-2243(87)90156-0 |issn=0301-2115 |issue=4 |pages=309–318 |periodical=European Journal of Obstetrics, Gynecology, and Reproductive Biology |pmid=2953634 |title=The fibrinolytic enzyme system in normal menstruation and excessive uterine bleeding and the effect of tranexamic acid |volume=24}}<!-- auto-translated from German by Module:CS1 translator --></ref>

The amount of iron lost in menstrual fluid is relatively small for most women.{{better source needed|date=February 2021}}<ref>{{cite web |title=Iron-deficiency is not something you get just for being a lady | vauthors = Clancy K |url=http://blogs.scientificamerican.com/context-and-variation/2011/07/27/iron-deficiency-anemia/ |publisher=SciAm |date=27 July 2011 |url-status=live |archive-url=https://web.archive.org/web/20120317152812/http://blogs.scientificamerican.com/context-and-variation/2011/07/27/iron-deficiency-anemia/ |archive-date=17 March 2012 }}</ref> In one study, premenopausal women who exhibited symptoms of [[iron deficiency (medicine)|iron deficiency]] were given [[Endoscopy|endoscopies]]. 86% of them actually had [[gastrointestinal disease]] and were at risk of being misdiagnosed simply because they were menstruating.{{primary source inline|date=February 2021}}<ref>{{cite journal | vauthors = Kepczyk T, Cremins JE, Long BD, Bachinski MB, Smith LR, McNally PR | title = A prospective, multidisciplinary evaluation of premenopausal women with iron-deficiency anemia | journal = The American Journal of Gastroenterology | volume = 94 | issue = 1 | pages = 109–115 | date = January 1999 | doi = 10.1111/j.1572-0241.1999.00780.x | pmid = 9934740 | s2cid = 25975251 }}</ref> Heavy menstrual bleeding, occurring monthly, can result in [[anemia]].<ref>{{cite journal | vauthors = Mansour D, Hofmann A, Gemzell-Danielsson K | title = A Review of Clinical Guidelines on the Management of Iron Deficiency and Iron-Deficiency Anemia in Women with Heavy Menstrual Bleeding | journal = Advances in Therapy | volume = 38 | issue = 1 | pages = 201–225 | date = January 2021 | pmid = 33247314 | pmc = 7695235 | doi = 10.1007/s12325-020-01564-y }}</ref>

===Hormonal changes===

{{excerpt|menstrual cycle|file=no|paragraphs=1,2}}

== Side effects==
===Menstrual health overview===
{{excerpt|Menstrual cycle#Menstrual health|paragraphs=1,2}}

===Moods and premenstrual syndrome (PMS)===
{{main|Menstruation and mental health}}
{{excerpt|Premenstrual syndrome}}

===Cramps===
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.<ref name="The prevalence and risk factors of">{{cite journal | vauthors = Ju H, Jones M, Mishra G | title = The prevalence and risk factors of dysmenorrhea | journal = Epidemiologic Reviews | volume = 36 | issue = 1 | pages = 104–113 | date = 1 January 2014 | pmid = 24284871 | doi = 10.1093/epirev/mxt009 | doi-access = free }}</ref> Among adult women, 2%–28% have pain severe enough to affect daily activity.<ref name="The prevalence and risk factors of"/> Severe symptoms that disrupt daily activities and functioning may be diagnosed as [[premenstrual dysphoric disorder]].<ref name="WH2020">{{cite web|date=12 July 2017|title=Premenstrual syndrome (PMS)|url=https://www.womenshealth.gov/menstrual-cycle/premenstrual-syndrome|access-date=3 January 2020|website=womenshealth.gov|language=en|archive-date=8 December 2016|archive-url=https://web.archive.org/web/20161208172815/https://www.womenshealth.gov/publications/our-publications/fact-sheet/premenstrual-syndrome.html|url-status=live}}</ref> 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.<ref name="AFP2011" />

When severe pelvic pain and bleeding suddenly occur or worsen during a cycle, this could be due to [[ectopic pregnancy]] and [[miscarriage|spontaneous abortion]]. This is checked by using a pregnancy test, ideally as soon as unusual pain begins, because ectopic pregnancies can be life‑threatening.<ref>{{cite web|title=Ectopic Pregnancy Clinical Presentation: History, Physical Examination|url=http://emedicine.medscape.com/article/2041923-clinical|url-status=live|archive-url=https://web.archive.org/web/20130329020606/http://emedicine.medscape.com/article/2041923-clinical|archive-date=29 March 2013|website=emedicine.medscape.com}}</ref>

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.<ref name="Dysmenorrhoea">{{cite journal | vauthors = Latthe PM, Champaneria R | title = Dysmenorrhoea | journal = BMJ Clinical Evidence | volume = 2014 | pages = 390–400 | date = October 2014 | pmid = 25338194 | pmc = 4205951 | doi = 10.1016/j.ajog.2017.08.108 }}</ref> About 1 in 5 women do not respond to NSAIDs and require alternative therapy, such as simple analgesics or heat pads.<ref>{{cite journal | vauthors = Oladosu FA, Tu FF, Hellman KM | title = Nonsteroidal antiinflammatory drug resistance in dysmenorrhea: epidemiology, causes, and treatment | journal = American Journal of Obstetrics and Gynecology | volume = 218 | issue = 4 | pages = 390–400 | date = April 2018 | pmid = 28888592 | pmc = 5839921 | doi = 10.1016/j.ajog.2017.08.108 }}</ref> 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.<ref name="Dysmenorrhoea"/>

One review found tentative evidence that acupuncture may be useful, at least in the short term.<ref>{{cite journal | vauthors = Woo HL, Ji HR, Pak YK, Lee H, Heo SJ, Lee JM, Park KS | title = The efficacy and safety of acupuncture in women with primary dysmenorrhea: A systematic review and meta-analysis | journal = Medicine | volume = 97 | issue = 23 | article-number = e11007 | date = June 2018 | pmid = 29879061 | pmc = 5999465 | doi = 10.1097/MD.0000000000011007 }}</ref> Another review found insufficient evidence to determine an effect.<ref>{{cite journal | vauthors = Smith CA, Armour M, Zhu X, Li X, Lu ZY, Song J | title = Acupuncture for dysmenorrhoea | journal = The Cochrane Database of Systematic Reviews | volume = 2016 | issue = 4 | article-number = CD007854 | date = April 2016 | pmid = 27087494 | pmc = 8406933 | doi = 10.1002/14651858.CD007854.pub3 }}</ref>

=== Interactions with other conditions ===
Known interactions between the menstrual cycle and certain health conditions include:

* Some women with [[Neurology|neurological conditions]] experience increased activity of their conditions at about the same time during each menstrual cycle. For example, drops in estrogen levels may trigger [[migraines]],{{medical citation needed|date=February 2021}} <ref>{{cite journal | vauthors = Reddy N, Desai MN, Schoenbrunner A, Schneeberger S, Janis JE | title = The complex relationship between estrogen and migraines: a scoping review | journal = Systematic Reviews | volume = 10 | issue = 1 | article-number = 72 | date = March 2021 | pmid = 33691790 | pmc = 7948327 | doi = 10.1186/s13643-021-01618-4 | doi-access = free }}</ref> especially when the woman who has migraines is also taking the birth control pill.
* Many women with [[epilepsy]] have more seizures in a pattern linked to the menstrual cycle; this is called "[[catamenial epilepsy]]".<ref name="pmid18164632">{{cite journal | vauthors = Herzog AG | title = Catamenial epilepsy: definition, prevalence pathophysiology and treatment | journal = Seizure | volume = 17 | issue = 2 | pages = 151–159 | date = March 2008 | pmid = 18164632 | doi = 10.1016/j.seizure.2007.11.014 | s2cid = 6903651 | doi-access = free }}</ref> Different patterns seem to exist (such as seizures coinciding with the time of menstruation, or coinciding with the time of ovulation), and the frequency with which they occur has not been firmly established.
* Research indicates that women have a significantly higher likelihood of [[anterior cruciate ligament]] injuries in the pre-ovulatory stage, than post-ovulatory stage.<ref>{{cite journal | vauthors = Renstrom P, Ljungqvist A, Arendt E, Beynnon B, Fukubayashi T, Garrett W, Georgoulis T, Hewett TE, Johnson R, Krosshaug T, Mandelbaum B, Micheli L, Myklebust G, Roos E, Roos H, Schamasch P, Shultz S, Werner S, Wojtys E, Engebretsen L | display-authors = 6 | title = Non-contact ACL injuries in female athletes: an International Olympic Committee current concepts statement | journal = British Journal of Sports Medicine | volume = 42 | issue = 6 | pages = 394–412 | date = June 2008 | pmid = 18539658 | pmc = 3920910 | doi = 10.1136/bjsm.2008.048934 }}</ref>

=== Sexual activity ===
{{Further|Culture and menstruation}}
Sexual feelings and behaviors change during the menstrual cycle. Before and during ovulation, high levels of estrogen and [[androgen]]s result in women having a relatively increased interest in sexual activity, and relatively lower interest directly prior to and during menstruation.<ref>{{cite book| vauthors = Levay S, Baldwin J, Baldwin J |title=Discovering Human Sexuality |publisher=Sinauer Associates, Inc. |year=2015 |isbn=978-1-60535-275-6 | location = Massachusetts |pages=44 |chapter=Women's Bodies|name-list-style=vanc}}</ref> Unlike other mammals, women may show interest in sexual activity across all days of the menstrual cycle, regardless of fertility.<ref>{{cite book| vauthors = Thornhill R, Gangestad SW |title=The Evolutionary Biology of Human Female Sexuality|publisher=Oxford University Press|year=2008|isbn=978-0-19-534099-0|location=New York|pages=12|chapter=Background and Overview of the Book|name-list-style=vanc}}</ref>

There is no reliable scientific evidence that would advise against [[sexual intercourse]] during menstruation based on medical grounds.{{medical citation needed|date=February 2021}}

=== Fertility aspects ===
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.<ref>{{cite web|title=My Fertile Period | work = DuoFertility | publisher = Cambridge Temperature Concepts Limited |url=http://www.duofertility.com/en/my-body/my-cycle/my-fertile-period.html|archive-url=https://web.archive.org/web/20081221225600/http://www.duofertility.com/en/my-body/my-cycle/my-fertile-period.html|archive-date=2008-12-21|access-date=2008-09-22}}</ref> 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.<ref>{{cite journal | vauthors = Creinin MD, Keverline S, Meyn LA | title = How regular is regular? An analysis of menstrual cycle regularity | journal = Contraception | volume = 70 | issue = 4 | pages = 289–292 | date = October 2004 | pmid = 15451332 | doi = 10.1016/j.contraception.2004.04.012 }}</ref> A variety of methods have been developed to help individual women [[Fertility testing|estimate the relatively fertile]] and the relatively infertile days in the cycle; these systems are called [[fertility awareness]].{{medical citation needed|date=February 2021}}

== Menstrual disorders ==<!-- [[Irregular]] refers to here -->
{{main|Menstrual disorder}}
Infrequent or irregular ovulation is called ''oligoovulation''.<ref>{{cite web|vauthors=Galan N|date=16 April 2008|title=Oligoovulation|url=http://pcos.about.com/od/glossary/g/oligoovulation.htm|access-date=12 October 2008|publisher=about.com|name-list-style=vanc|archive-date=3 March 2016|archive-url=https://web.archive.org/web/20160303165958/http://pcos.about.com/od/glossary/g/oligoovulation.htm}}</ref> 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]].<ref name="tcoyf3">{{cite book | vauthors = Weschler T | year=2002 | title=Taking Charge of Your Fertility | url=https://archive.org/details/takingchargeofyo00toni | url-access=registration | page= 107 | archive-url = https://archive.org/details/takingchargeofyo00toni/page/107 | archive-date = 26 September 2011 | edition=Revised | publisher=HarperCollins | location=New York | isbn=978-0-06-093764-5 }}</ref> Anovulatory cycles commonly occur before [[menopause]] (perimenopause) and in women with [[polycystic ovary syndrome]].<ref name="emed2">{{EMedicine|med|146|Anovulation}}</ref>

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]]''.<ref name="emed1">{{EMedicine|ped|2781|Menstruation Disorders}}</ref> Heavy menstruation that occurs frequently and irregularly is ''[[menometrorrhagia]]''. The term for cycles with intervals exceeding 35 days is ''[[oligomenorrhea]]''.<ref name="afp">{{cite journal | vauthors = Oriel KA, Schrager S | title = Abnormal uterine bleeding | journal = American Family Physician | volume = 60 | issue = 5 | pages = 1371–80; discussion 1381–2 | date = October 1999 | pmid = 10524483 | url = http://www.aafp.org/link_out?pmid=10524483 }}</ref> [[Amenorrhea]] refers to more than three<ref name="emed1"/> to six<ref name="afp" /> months without menses (while not being pregnant) during a woman's reproductive years. The term for painful periods is ''[[dysmenorrhea]]''.

There is a wide spectrum of differences in how women experience menstruation. There are several ways that someone's [[menstrual cycle]] can differ from the norm:
{| class="wikitable"
|-
! Term
! Meaning
|-
|[[Oligomenorrhea]]
| Infrequent periods
|-
|[[Hypomenorrhea]]
| Short or light periods
|-
|[[Polymenorrhea]]
| Frequent periods (more frequently than every 21 days)
|-
|[[Hypermenorrhea]]
| Heavy or long periods (soaking a [[sanitary napkin]] or [[tampon]] every hour, menstruating longer than 7 days)
|-
|[[Dysmenorrhea]]
| Painful periods
|-
|[[Intermenstrual bleeding]]
| Breakthrough bleeding (also called spotting)
|-
|[[Amenorrhea]]
| Absent periods
|}

Extreme psychological stress can also result in periods stopping.<ref>{{cite journal | vauthors = Meczekalski B, Katulski K, Czyzyk A, Podfigurna-Stopa A, Maciejewska-Jeske M | title = Functional hypothalamic amenorrhea and its influence on women's health | journal = Journal of Endocrinological Investigation | volume = 37 | issue = 11 | pages = 1049–1056 | date = November 2014 | pmid = 25201001 | pmc = 4207953 | doi = 10.1007/s40618-014-0169-3 }}</ref> More severe symptoms of anxiety or depression may be signs of [[premenstrual dysphoric disorder]] (PMDD) which is a depressive disorder.<ref>{{cite book | vauthors = Mishra S, Elliott H, Marwaha R  |chapter=Premenstrual Dysphoric Disorder |title=StatPearls |date=2022 |publisher=StatPearls Publishing |id={{NCBIBook2|NBK532307}} |pmid=30335340 }}</ref>

[[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.{{medical citation needed|date=February 2021}}

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.<ref>{{cite web|title=Health risks of female genital mutilation (FGM)|url=https://www.who.int/reproductivehealth/topics/fgm/health_consequences_fgm/en/|archive-url=https://web.archive.org/web/20141129035132/http://www.who.int/reproductivehealth/topics/fgm/health_consequences_fgm/en/|archive-date=29 November 2014|website=World Health Organization}}</ref>

=== Dysmenorrhea ===
{{Excerpt|Dysmenorrhea}}

== Menstrual hygiene management ==
{{Main|Menstrual hygiene management|Feminine hygiene}}
{{multiple image
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| image1 = Everyday_maxipad.jpg
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| alt1 = Disposable sanitary napkin
| caption1 = Disposable [[sanitary napkin]]
| image2 = Elements_of_a_tampon_with_applicator.jpg
| width2 = {{#expr: (142 * 400 / 300) round 0}}
| alt2 = Tampon in plastic applicator
| caption2 = The elements of a [[tampon]] with applicator. Left: the bigger tube ("penetrator"). Center: cotton tampon with attached string. Right: the narrower tube.
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{{multiple image
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| image1 = Coupe-menstruelle.jpg
| width1 = {{#expr: (150 * 591 / 713) round 0}}
| alt1 = Menstrual cup
| caption1 = [[Menstrual cup]]
| image2 = Clothpad.jpg
| width2 = {{#expr: (150 * 320 / 216) round 0}}
| alt2 = Cloth menstrual pad
| caption2 = [[Cloth menstrual pad]]
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}}
Menstrual products (also called "[[feminine hygiene]]" products) are made to absorb or catch menstrual blood. A number of different products are available – some are disposable, some are reusable. Where women can afford it, items used to absorb or catch menses are usually commercially manufactured products. Menstruating women manage menstruation primarily by wearing menstrual products such as tampons, napkins or menstrual cups to catch the menstrual blood.

The main disposable products (commercially manufactured) include:
*[[Sanitary napkin]]s (also called sanitary towels or pads) – Rectangular pieces of material worn attached to the underwear to absorb menstrual flow, often with an adhesive backing to hold the pad in place. Disposable pads may contain [[wood pulp]] or [[gel]] products, usually with a plastic lining and bleached.
*[[Tampon]]s – Disposable cylinders of treated [[rayon]]/cotton blends or all-cotton fleece, usually bleached, that are inserted into the vagina to absorb menstrual flow.

The main reusable products include:
*[[Menstrual cup]]s – A firm, flexible bell-shaped device worn inside the vagina to collect menstrual flow. 
*[[Cloth menstrual pad|Reusable cloth pads]] – Pads that are made of cotton (often [[organic farming|organic]]), [[terrycloth]], or [[flannel]], and may be handsewn (from material or reused old clothes and towels) or store-bought.
*[[Period underwear|Padded panties or period-proof underwear]] – Reusable cloth (usually cotton) [[undergarment|underwear]] with extra absorbent layers sewn in to absorb flow. 

Due to poverty, some women cannot afford commercial feminine hygiene products.<ref name="Kaur_2018">{{cite journal | vauthors = Kaur R, Kaur K, Kaur R | title = Menstrual Hygiene, Management, and Waste Disposal: Practices and Challenges Faced by Girls/Women of Developing Countries | journal = Journal of Environmental and Public Health | volume = 2018 | article-number = 1730964 | date = 2018 | pmid = 29675047 | pmc = 5838436 | doi = 10.1155/2018/1730964 | doi-access = free }}</ref><ref>{{cite news |title=Girls 'too poor' to buy sanitary protection missing school |url=https://www.bbc.com/news/uk-39266056 |work=BBC News |date=14 March 2017 |access-date=27 April 2019 |archive-date=27 April 2019 |archive-url=https://web.archive.org/web/20190427120746/https://www.bbc.com/news/uk-39266056 |url-status=live }}</ref> Instead, they use materials found in the environment or other improvised materials.<ref>{{cite thesis |vauthors=Chin L |title=Period of shame - The effects of menstrual hygiene management on rural women and girls' quality of life in Savannakhet, Laos |date=2014 |url=https://www.lunduniversity.lu.se/lup/publication/4442938 |access-date=7 December 2022 |archive-date=7 December 2022 |archive-url=https://web.archive.org/web/20221207185900/https://www.lunduniversity.lu.se/lup/publication/4442938 |url-status=live }}</ref><ref>{{cite journal | vauthors = House S, Mahon T, Cavill S |title=Menstrual Hygiene Matters: a resource for improving menstrual hygiene around the world |journal=Reproductive Health Matters |date=2013 |volume=21 |issue=41 |pages=257–259 |jstor=43288983 }}</ref> "[[Period poverty]]" is a global issue affecting women and girls who do not have access to safe, hygienic sanitary products.<ref>{{Cite web|title=Period poverty|url=https://www.actionaid.org.uk/about-us/what-we-do/womens-economic-empowerment/period-poverty|website=ActionAid UK|access-date=3 June 2020|archive-date=30 October 2019|archive-url=https://web.archive.org/web/20191030213257/https://www.actionaid.org.uk/about-us/what-we-do/womens-economic-empowerment/period-poverty|url-status=live}}</ref> In addition, solid waste disposal systems in developing countries are often lacking, which means women have no proper place to dispose used products, such as pads.<ref>{{cite report | vauthors = Kjellén M, Pensulo C, Nordqvist P, Fogde M | title = Global Review of Sanitation System Trends and Interactions with Menstrual Management Practices: Report for the Menstrual Management and Sanitation Systems Project. | url = https://www.susana.org/en/knowledge-hub/resources-and-publications/library/details/1556 | publisher = Stockholm Environment Institute (SEI) | location = Stockholm, Sweden }}</ref> Inappropriate disposal of used materials also creates pressures on sanitation systems as menstrual hygiene products can create blockages of toilets, pipes and sewers.<ref name="Kaur_2018" /> In the UK research has shown that for women who are [[Allotment (gardening)|allotment]] growers, access to sanitation for menstrual hygiene management is limited.<ref>{{Cite journal |last=Cox |first=Elizabeth |date=2023-12-12 |title=Leaks and pees: How women allotment gardeners manage bodily mess and the remains of early loss |url=https://thesociologicalreview.org/magazine/december-2023/mess/leaks-and-pees/ |journal=The Sociological Review Magazine |language=English |doi=10.51428/tsr.tour5403|s2cid=265560522 |doi-access=free }}</ref>

==Menstrual suppression==
{{Main|Menstrual suppression}}

===Due to hormonal contraception===
{{Main|Hormonal contraception}}
[[File:pillpacketopen.jpg|thumb|right|Half-used blister pack of a combined oral contraceptive. The white pills are [[placebos]], mainly for the purpose of reminding the woman to continue taking the pills.]]
Menstruation can be delayed by the use of [[progesterone]] or [[progestin]]s. 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.<ref name="Goldstuck2011">{{cite journal | vauthors = Goldstuck N |title=Progestin potency – Assessment and relevance to choice of oral contraceptives |journal=Middle East Fertility Society Journal |date=1 December 2011 |volume=16 |issue=4 |pages=248–253 |doi=10.1016/j.mefs.2011.08.006 |doi-access=free }}</ref>

[[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 oral contraceptive pill|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 [[Combined oral contraceptive pill#Non-contraceptive use|some menstrual symptoms and syndromes which affect menstruation]], such as [[polycystic ovary syndrome]] (PCOS), [[endometriosis]], [[adenomyosis]], [[amenorrhea]], [[Dysmenorrhea|menstrual cramps]], [[menstrual migraine]]s, [[Heavy menstrual bleeding|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.<ref>{{cite web|url=http://www.youngwomenshealth.org/med-uses-ocp.html|title=Medical Uses of the Birth Control Pill|last=CYWH Staff|date=2011-10-18|access-date=1 February 2013|archive-date=5 February 2013|archive-url=https://web.archive.org/web/20130205071228/http://www.youngwomenshealth.org/med-uses-ocp.html}}</ref><ref name="auto">{{cite journal | vauthors = Curtis KM, Tepper NK, Jatlaoui TC, Berry-Bibee E, Horton LG, Zapata LB, Simmons KB, Pagano HP, Jamieson DJ, Whiteman MK | display-authors = 6 | title = U.S. Medical Eligibility Criteria for Contraceptive Use, 2016 | journal = MMWR. Recommendations and Reports | volume = 65 | issue = 3 | pages = 1–103 | date = July 2016 | pmid = 27467196 | doi = 10.15585/mmwr.rr6503a1 | doi-access = free }}</ref>

Using the [[Combined oral contraceptive pill|combined birth control pill]], it is also possible for a woman to delay or eliminate menstrual periods, a practice called [[menstrual suppression]].<ref>{{cite web|title=Delaying your period with birth control pills|url=http://www.mayoclinic.com/health/womens-health/WO00069|publisher=Mayo Clinic|access-date=20 September 2011|url-status=live|archive-url=https://web.archive.org/web/20110926085226/http://www.mayoclinic.com/health/womens-health/WO00069|archive-date=26 September 2011}}</ref> Some women do this simply for convenience in the short-term,<ref>{{cite web|url=http://www.nhs.uk/chq/Pages/830.aspx?CategoryID=60&SubCategoryID=179|title=How can I delay my period while on holiday?|publisher=National Health Service, United Kingdom|archive-url=https://web.archive.org/web/20110805003602/http://www.nhs.uk/chq/Pages/830.aspx?CategoryID=60&SubCategoryID=179|archive-date=5 August 2011|url-status=live|access-date=20 September 2011}}</ref> 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.<ref name=":4">{{cite journal | vauthors = Strandjord SE, Rome ES | title = Monthly Periods--Are They Necessary? | journal = Pediatric Annals | volume = 44 | issue = 9 | pages = e231–e236 | date = September 2015 | pmid = 26431242 | doi = 10.3928/00904481-20150910-11 }}</ref>

=== Due to breastfeeding ===
{{main|Lactational amenorrhea}}
[[Breastfeeding]] causes negative feedback to occur on pulse secretion of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH).<ref>{{Cite book |url=https://www.ncbi.nlm.nih.gov/books/NBK148970/ |title=Infant and Young Child Feeding |date=2009 |publisher=World Health Organization |language=en |access-date=12 August 2022 |archive-date=19 January 2018 |archive-url=https://web.archive.org/web/20180119051121/https://www.ncbi.nlm.nih.gov/books/NBK148970/ |url-status=live }}</ref> 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.<ref name="mcneilly">{{cite journal | vauthors = McNeilly AS | title = Lactational control of reproduction | journal = Reproduction, Fertility, and Development | volume = 13 | issue = 7–8 | pages = 583–590 | year = 2001 | pmid = 11999309 | doi = 10.1071/RD01056 }}</ref> Suppression of ovulation is more likely when suckling occurs more frequently.<ref name="autogenerated1">{{cite book | vauthors = Kippley J, Kippley S | year=1996 | title=The Art of Natural Family Planning | edition=4th | publisher=The Couple to Couple League | location=Cincinnati, OH | isbn=0-926412-13-2 | page=347}}</ref> The production of [[prolactin]] in response to suckling is important to maintaining lactational amenorrhea.<ref>{{cite journal | vauthors = Stallings JF, Worthman CM, Panter-Brick C, Coates RJ | title = Prolactin response to suckling and maintenance of postpartum amenorrhea among intensively breastfeeding Nepali women | journal = Endocrine Research | volume = 22 | issue = 1 | pages = 1–28 | date = February 1996 | pmid = 8690004 | doi = 10.3109/07435809609030495 }}</ref> 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.<ref>{{cite web | title = Breastfeeding: Does It Really Space Babies? | work = The Couple to Couple League International | publisher = Internet Archive | date = 17 January 2008 | url = http://www.ccli.org/nfp/ebf/spacebabies.php | access-date = 21 September 2008 |archive-url = https://web.archive.org/web/20080117232155/http://www.ccli.org/nfp/ebf/spacebabies.php |archive-date = 17 January 2008}}, which cites:

:{{cite journal | vauthors = Kippley SK, Kippley JF | title = The relation between breastfeeding and amenorrhea: report of a survey | journal = JOGN Nursing; Journal of Obstetric, Gynecologic, and Neonatal Nursing | volume = 1 | issue = 4 | pages = 15–21 | date = November–December 1972 | pmid = 4485271 | doi = 10.1111/j.1552-6909.1972.tb00558.x | ref = none }}
:{{cite journal | vauthors=Kippley SK|title=Breastfeeding survey results similar to 1971 study | journal=The CCL News | date=November–December 1986 | volume=13|issue=3 | page=10|ref=none}}
:{{cite journal | vauthors=Kippley SK|title=Breastfeeding survey results similar to 1971 study | journal=The CCL News | date=January–February 1987 | volume=13|issue=4 | page=5|ref=none}}</ref>

==Society and culture==
{{Main|Culture and menstruation}}
[[File:Amra Padatik India.jpg|thumb|Amra Padatik India, celebration of [[Menstrual Hygiene Day]] in India]]

=== Etymology and terminology ===
The word ''menstruation'' is etymologically related to ''[[moon]]''. The terms ''menstruation'' and ''menses'' are derived from the [[Latin]] {{lang|la|mensis}} {{gloss|month}}, which in turn relates to the [[ancient Greek]] {{transliteration|grc|mene}} {{gloss|moon}} and to the roots of the English words ''month'' and ''moon''.<ref name="Allen, Kevin 2007 239">{{cite book |title=The Reluctant Hypothesis: A History of Discourse Surrounding the Lunar Phase Method of Regulating Conception |vauthors=Allen K |publisher=Lacuna Press |year=2007 |isbn=978-0-9510974-2-7 |page=239 |name-list-style=vanc}}</ref>

Some organizations have begun to use the term "menstruator" instead of "menstruating women", a term that has been in use since at least 2010.<ref name="chapter 68">{{cite book |title=The Palgrave Handbook of Critical Menstruation Studies |vauthors=Rydström K |chapter=Degendering Menstruation: Making Trans Menstruators Matter |date=2020 |publisher=Springer Singapore |isbn=978-981-15-0613-0 |veditors=Bobel C, Winkler IT, Fahs B, Hasson KA |location=Singapore |pages=945–959 |language=en |doi=10.1007/978-981-15-0614-7_68 |pmid=33347169 |doi-access=free}}</ref> ''Menstruator'' is used by activists and scholars in order to "express solidarity with women who do not menstruate, [[transgender men]] who do, and [[intersex]]ual and [[genderqueer]] individuals".<ref name="chapter 68" />{{rp|950}} The term can be contentious between different schools of feminist thought; however, the argument is made that since gender identities are lived, the reality is that people of different genders menstruate.<ref name="chapter 68" />{{rp|950}} The term "people who menstruate" is also used.<ref>{{cite news |name-list-style=vanc |date=7 June 2020 |title=J.K. Rowling accused of transphobia after mocking 'people who menstruate' headline |language=en |work=NBC News |url=https://www.nbcnews.com/feature/nbc-out/j-k-rowling-accused-transphobia-after-mocking-people-who-menstruate-n1227071 |access-date=9 February 2022 |vauthors=Madani D |archive-date=9 February 2022 |archive-url=https://web.archive.org/web/20220209142947/https://www.nbcnews.com/feature/nbc-out/j-k-rowling-accused-transphobia-after-mocking-people-who-menstruate-n1227071 |url-status=live }}</ref>

=== Traditions, taboos and education ===
{{See also|Menstruation in Islam|Woman prayer|Istihadha}}
Many religions have menstruation-related traditions, for example: Islam prohibits sexual contact with women during menstruation in the [[2nd chapter of the Quran]].<ref name="Quran">{{Cite web|url=https://quran.com/al-baqarah/222|title=Surah Al-Baqarah - 222|website=Quran.com|access-date=28 August 2022|archive-date=28 August 2022|archive-url=https://web.archive.org/web/20220828013825/https://quran.com/al-baqarah/222|url-status=live}}</ref> 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.<ref name="ahadith">{{Cite web | url = http://ahadith.co.uk/chapter.php?cid=28 | vauthors = Bukhari S | title = Chapter: 6, Menstrual Periods | work = ahadith.co.uk | access-date = 18 September 2018 | archive-date = 30 September 2018 | archive-url = https://web.archive.org/web/20180930090803/http://ahadith.co.uk/chapter.php?cid=28 | url-status = live }}</ref> 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.<ref>Leviticus 15:19-30, 18:19, 20:18</ref> In [[Hinduism]], menstruating women are [[Culture and menstruation#Hinduism|traditionally considered ritually impure]] and given rules to follow.<ref>{{cite journal | vauthors = Dunnavant NC, Roberts TA | title = Restriction and renewal, pollution and power, constraint and community: The paradoxes of religious women's experiences of menstruation. | journal = Sex Roles | date = January 2013 | volume = 68 | issue = 1 | pages = 12–31 | doi = 10.1007/s11199-012-0132-8 | s2cid = 144688091 }}</ref><ref>{{cite journal | vauthors = Garg S, Anand T | title = Menstruation related myths in India: strategies for combating it | journal = Journal of Family Medicine and Primary Care | volume = 4 | issue = 2 | pages = 184–186 | date = 2015 | pmid = 25949964 | pmc = 4408698 | doi = 10.4103/2249-4863.154627 | doi-access = free }}</ref> In Zoroastrianism, if a woman's menses did not stop after nine days, it was considered the work of the [[Daeva|daēvas]].<ref>{{Cite book |last=Wolff |first=Fritz |title=Avesta: The Sacred Books Parsen |isbn=}}</ref>

Menstruation education is frequently taught in combination with sex education at school in [[Western world|Western countries]], although girls may prefer their mothers to be the primary source of information about menstruation and puberty.<ref name="Sooki">{{cite journal | vauthors = Sooki Z, Shariati M, Chaman R, Khosravi A, Effatpanah M, Keramat A | title = The Role of Mother in Informing Girls About Puberty: A Meta-Analysis Study | journal = Nursing and Midwifery Studies | volume = 5 | issue = 1 | article-number = e30360 | date = March 2016 | pmid = 27331056 | pmc = 4915208 | doi = 10.17795/nmsjournal30360 }}</ref> Information about menstruation is often shared among friends and peers, which may promote a more positive outlook on puberty.<ref>{{cite journal | vauthors = Hatami M, Kazemi A, Mehrabi T | title = Effect of peer education in school on sexual health knowledge and attitude in girl adolescents | journal = Journal of Education and Health Promotion | volume = 4 | page = 78 | date = 2015-12-30 | pmid = 27462620 | pmc = 4944604 |doi = 10.4103/2277-9531.171791  |doi-access=free}}</ref> The quality of menstrual education in a society determines the accuracy of people's understanding of the process.<ref name = "Allen_2011">{{cite journal| vauthors = Allen KR, Kaestle CE, Goldberg AE | title = More than just a punctuation mark: How boys and young men learn about menstruation | journal = Journal of Family Issues | date = February 2011 | volume = 32 | issue = 2 | pages = 129–56 | doi = 10.1177/0192513x10371609 | s2cid = 145531604 }}</ref> 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.<ref name="Allen_2011" /> Effective educational programs are essential to providing children and adolescents with clear and accurate information about menstruation. Schools can be an appropriate place for menstrual education to take place.<ref name="Kirby_2002">{{cite journal | vauthors = Kirby D | title = The impact of schools and school programs upon adolescent sexual behavior | journal = Journal of Sex Research | volume = 39 | issue = 1 | pages = 27–33 | date = February 2002 | pmid = 12476253 | doi = 10.1080/00224490209552116 | s2cid = 45063072 }}</ref> Programs led by peers or third-party agencies are another option.<ref name="Kirby_2002" /> Low-income girls are less likely to receive proper sex education on puberty, leading to a decreased understanding of why menstruation occurs and the associated physiological changes that take place. This has been shown to cause the development of a negative attitude towards menstruation.<ref>{{cite journal | vauthors = Herbert AC, Ramirez AM, Lee G, North SJ, Askari MS, West RL, Sommer M | title = Puberty Experiences of Low-Income Girls in the United States: A Systematic Review of Qualitative Literature From 2000 to 2014 | journal = The Journal of Adolescent Health | volume = 60 | issue = 4 | pages = 363–379 | date = April 2017 | pmid = 28041680 | doi = 10.1016/j.jadohealth.2016.10.008 }}</ref>

==== Seclusion during menstruation ====

{{Further|Chhaupadi|Seclusion of girls at puberty}}

[[File:Mass-Community_Health_Teaching.JPG|left|thumb|Awareness raising through education is taking place among women and girls to modify or eliminate the practice of [[chhaupadi]] in [[Nepal]].]]
In some cultures, women were isolated during menstruation due to menstrual [[taboo]]s.<ref name="Gottlieb2020">{{cite book | veditors = Bobel C, Winkler IG, Fahs B, Hasson KA, Kissling EA, Roberts T | title = The Palgrave Handbook of Critical Menstruation Studies | vauthors = Gottlieb A | chapter = Menstrual Taboos: Moving Beyond the Curse | year = 2020 | pages = 143–162 | publisher = Palgrave Macmillan | isbn = 978-981-15-0614-7 | doi = 10.1007/978-981-15-0614-7_14 | pmid = 33347165 | s2cid = 226694557 | chapter-url = https://www.ncbi.nlm.nih.gov/books/NBK565616/ | access-date = 27 February 2021 | archive-date = 7 April 2022 | archive-url = https://web.archive.org/web/20220407151014/https://www.ncbi.nlm.nih.gov/books/NBK565616/ | url-status = live }}</ref> 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.<ref name="KleinmanGood1985">{{cite book| vauthors = Kleinman A, Good BJ |title=Culture and Depression: Studies in the Anthropology and Cross-Cultural Psychiatry of Affect and Disorder|url=https://books.google.com/books?id=27UwDwAAQBAJ&pg=PA182|year=1985|publisher=University of California Press|isbn=978-0-520-05883-5|pages=203–204}}</ref> A 1983 report found women refraining  from household chore during this period in India.<ref name="DelaneyLupton1988">{{cite book| vauthors = Delaney J, Lupton MJ, Toth E |title=The Curse: A Cultural History of Menstruation|url=https://books.google.com/books?id=njfQfrMr31EC&pg=PR9|year=1988|publisher=University of Illinois Press|isbn=978-0-252-01452-9|page=14}}</ref> [[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 [[Impurity|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.<ref>{{cite web|date=August 2011|title=Nepal: Emerging from menstrual quarantine|url=http://www.refworld.org/cgi-bin/texis/vtx/rwmain?page=publisher&publisher=IRIN&type=&coi=NPL&docid=4e3f7ae82&skip=0|work=United Nations High Commissioner for Refugees (UNHCR)|access-date=23 February 2021|archive-date=29 November 2014|archive-url=https://web.archive.org/web/20141129030810/http://www.refworld.org/cgi-bin/texis/vtx/rwmain?page=publisher&publisher=IRIN&type=&coi=NPL&docid=4e3f7ae82&skip=0|url-status=live}}</ref><ref>{{cite web|vauthors=Sharma S|date=15 September 2005|title=Women hail menstruation ruling|url=http://news.bbc.co.uk/2/hi/south_asia/4250506.stm|work=BBC News|access-date=17 November 2014|archive-date=31 August 2010|archive-url=https://web.archive.org/web/20100831235652/http://news.bbc.co.uk/2/hi/south_asia/4250506.stm|url-status=live}}</ref> Women and girls in cultures which practice such seclusion are often confined to [[menstruation hut]]s, which are places of isolation used by cultures with strong menstrual [[taboo]]s. 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."<ref name="FAWCO_2019">{{cite web|vauthors=Canning M|date=September 2019|title=Menstrual Health and the Problem with Menstrual Stigma|url=https://www.fawco.org/global-issues/target-program/health/blog-health-matters/4146-sample|work=The Federation of American Women's Clubs Overseas, Inc. (FAWCO)|name-list-style=vanc|access-date=23 February 2021|archive-date=14 August 2020|archive-url=https://web.archive.org/web/20200814202359/https://www.fawco.org/global-issues/target-program/health/blog-health-matters/4146-sample|url-status=live}}</ref> Not all cultures villainize menstruation, the Beng people of West Africa consider menstrual blood as sacred and recognize its significance in reproduction.<ref>{{Cite web |date=2023-11-29 |title=Egyptians used papyrus—and other ways of handling periods through the years |url=https://www.nationalgeographic.com/history/article/periods-menstruation-women-history-ancient-egypt |access-date=2023-12-01 |website=History |language=en}}</ref>

=== Beliefs around synchrony ===

==== Effects of the moon ====
{{see also|Lunar effect}}
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.<ref>{{cite book|url=https://books.google.com/books?id=F_NaW1ZcSSAC&pg=PA361|title=Vertebrate Endocrinology|date=2013|publisher=Academic Press|isbn=978-0-12-396465-6|edition=5|page=361}}</ref> The relationship is believed to be a coincidence.<ref>{{cite book| vauthors = Gutsch WA |title=1001 things everyone should know about the universe|date=1997|publisher=Doubleday|isbn=978-0-385-48223-3|edition=1st|location=New York|page=57 }}</ref><ref>{{cite book| vauthors = Barash DP |title=How women got their curves and other just-so stories evolutionary enigmas|date=2009|publisher=Columbia University Press|isbn=978-0-231-51839-0|edition=[Online-Ausg.].|location=New York|chapter=Synchrony and Its Discontents|chapter-url=https://books.google.com/books?id=fZM2AAAAQBAJ&pg=PT64 }}</ref> Light exposure does not appear to affect the menstrual cycle in humans.<ref name="Kris2013">{{cite book| vauthors =  Lopez KH |url=https://books.google.com/books?id=M4kEdSnS-pkC&pg=PA53|title=Human Reproductive Biology|date=2013|publisher=Academic Press|isbn=978-0-12-382185-0|page=53|archive-url=https://web.archive.org/web/20150621165031/https://books.google.ca/books?id=M4kEdSnS-pkC&pg=PA53|archive-date=21 June 2015|url-status=live}}</ref> A meta-analysis of studies from 1996 showed no correlation between the human menstrual cycle and the lunar cycle,<ref>{{cite web | vauthors = Adams C | date = 24 September 1999 | work = The Straight Dope | url = http://www.straightdope.com/classics/a990924.html | archive-url = https://web.archive.org/web/20060615102004/http://www.straightdope.com/classics/a990924.html | archive-date = 15 June 2006 | title = What's the link between the moon and menstruation? | access-date = 6 June 2006 }}: {{cite book| vauthors = Abell GO, Singer B |title=Science and the Paranormal: Probing the Existence of the Supernatural|publisher=Scribner Book Company|year=1983|isbn=978-0-684-17820-2|author-link=George Ogden Abell|name-list-style=vanc}}</ref> nor did data analyzed by period-tracking app Clue, submitted by 1.5{{nbsp}}million women, of 7.5{{nbsp}}million menstrual cycles; however, the lunar cycle and the average menstrual cycle were found to be basically equal in length.<ref name="Clue">{{cite web|date=3 December 2018|title=The myth of moon phases and menstruation|url=https://helloclue.com/articles/cycle-a-z/myth-moon-phases-menstruation|access-date=3 December 2018|publisher=Clue|archive-date=30 November 2018|archive-url=https://web.archive.org/web/20181130164547/https://helloclue.com/articles/cycle-a-z/myth-moon-phases-menstruation|url-status=live}}</ref>

==== Cohabitation ====
Beginning in 1971, some research suggested that menstrual cycles of cohabiting women became synchronized ([[menstrual synchrony]]).<ref name="Mclintock">{{cite journal | vauthors = Stern K, McClintock MK | title = Regulation of ovulation by human pheromones | journal = Nature | volume = 392 | issue = 6672 | pages = 177–179 | date = March 1998 | pmid = 9515961 | doi = 10.1038/32408 | bibcode = 1998Natur.392..177S | s2cid = 4426700 }}</ref> Subsequent research has called this hypothesis into question.<ref>{{cite web|vauthors=Adams C|author-link=Cecil Adams|date=20 December 2002|title=Does menstrual synchrony really exist?|url=http://www.straightdope.com/columns/021220.html|access-date=10 January 2007|work=The Straight Dope|publisher=The Chicago Reader|name-list-style=vanc|archive-date=20 July 2008|archive-url=https://web.archive.org/web/20080720115936/http://www.straightdope.com/columns/021220.html}}</ref> A 2013 review concluded that menstrual synchrony likely does not exist.<ref name="Harris2013">{{cite journal | vauthors = Harris AL, Vitzthum VJ | title = Darwin's legacy: an evolutionary view of women's reproductive and sexual functioning | journal = Journal of Sex Research | volume = 50 | issue = 3–4 | pages = 207–246 | year = 2013 | pmid = 23480070 | doi = 10.1080/00224499.2012.763085 | s2cid = 30229421 }}</ref>

=== Work ===
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.<ref name="Matchar_2014">{{cite news|vauthors=Matchar E|date=16 May 2014|title=Should Paid 'Menstrual Leave' Be a Thing?|url=https://www.theatlantic.com/health/archive/2014/05/should-women-get-paid-menstrual-leave-days/370789/|work=The Atlantic|access-date=21 June 2015|name-list-style=vanc|archive-date=29 April 2018|archive-url=https://web.archive.org/web/20180429054951/https://www.theatlantic.com/health/archive/2014/05/should-women-get-paid-menstrual-leave-days/370789/|url-status=live}}</ref> Countries with policies include Japan, Taiwan, Indonesia, and South Korea.<ref name= "Levitt_2020">{{cite book | veditors = Bobel C, Winkler IG, Fahs B, Hasson KA, Kissling EA, Roberts T | title = The Palgrave Handbook of Critical Menstruation Studies | vauthors = Levitt RA, Barnack-Tavlaris JL | chapter = Addressing Menstruation in the Workplace: The Menstrual Leave Debate | year = 2020 | pages = 561–575 | publisher = Palgrave Macmillan | isbn = 978-981-15-0614-7 | doi = 10.1007/978-981-15-0614-7_43 | pmid = 33347190 | s2cid = 226619907 | chapter-url = https://www.ncbi.nlm.nih.gov/books/NBK565643/ }}</ref><ref name= King2021>King S. (2021) Menstrual Leave: Good Intention, Poor Solution. In: Hassard J., Torres L.D. (eds) ''Aligning Perspectives in Gender Mainstreaming. Aligning Perspectives on Health, Safety and Well-Being.'' Springer, Cham. {{doi|10.1007/978-3-030-53269-7_9}}</ref> The practice is controversial due to concerns that it bolsters the perception of women as weak, inefficient workers,<ref name="Matchar_2014" /> as well as concerns that it is unfair to men,<ref>{{cite web|vauthors=Price C|date=11 October 2006|title=Should women get paid menstruation leave?|url=http://www.salon.com/2006/10/11/menstruation_4/|access-date=16 March 2016|website=Salon|name-list-style=vanc|archive-date=27 March 2019|archive-url=https://web.archive.org/web/20190327123049/https://www.salon.com/2006/10/11/menstruation_4/|url-status=live}}</ref><ref>{{Cite web|title=Menstrual Leave: Delightful or Discriminatory?|url=http://lipmag.com/culture/menstrual-leave-delightful-or-discriminatory/|access-date=16 March 2016|website=Lip Magazine|date=4 August 2013|archive-date=27 March 2019|archive-url=https://web.archive.org/web/20190327090204/http://lipmag.com/culture/menstrual-leave-delightful-or-discriminatory/|url-status=live}}</ref> and that it furthers gender stereotypes and the medicalization of menstruation.<ref name="Levitt_2020" />

== Other mammals ==
{{Main|Menstrual cycle#Evolution and other species|Menstruation (mammal)}}

Most [[female mammals]] have an [[estrous cycle]], but not all have a menstrual cycle that results in menstruation. [[Menstruation (mammal)|Menstruation in mammals]] occurs in some close evolutionary relatives such as chimpanzees.<ref name="strassmann">{{cite journal | vauthors = Strassmann BI | title = The evolution of endometrial cycles and menstruation | journal = The Quarterly Review of Biology | volume = 71 | issue = 2 | pages = 181–220 | date = June 1996 | pmid = 8693059 | doi = 10.1086/419369 | s2cid = 6207295 }}</ref>

== See also ==
* [[Niddah]] (Jewish laws of menstruation)

== References ==
{{reflist}}

==Sources==
* {{cite book |vauthors= Else-Quest N, Hyde JS |title= The Psychology of Women and Gender: Half the Human Experience |location= Los Angeles |publisher= [[SAGE Publishing]]|date= 2021 |edition = 10th |isbn= 978-1-544-39360-5 |chapter= Psychology, gender, and health: psychological aspects of the menstrual cycle }}
* {{cite book |vauthors=[[Jerilynn Prior|Prior JC]]| veditors = Ussher JM, Chrisler JC, Perz J |title=Routledge International Handbook of Women's Sexual and Reproductive Health |publisher=[[Routledge]] |edition= 1st|date=2020 |chapter=The menstrual cycle: its biology in the context of silent ovulatory disturbances |isbn= 978-1-138-49026-0 |location=[[Abingdon, Oxon]]|oclc=1121130010}}

== Further reading ==
* {{cite book|title=The Palgrave Handbook of Critical Menstruation Studies |url=https://link.springer.com/book/10.1007/978-981-15-0614-7 |isbn=978-981-15-0614-7 |year=2020 |publisher=[[Springer Nature]]|doi=10.1007/978-981-15-0614-7 |pmid=33347099 |editor-last1=Bobel |editor-last2=Winkler |editor-last3=Fahs |editor-last4=Hasson |editor-last5=Kissling |editor-last6=Roberts |editor-first1=Chris |editor-first2=Inga T. |editor-first3=Breanne |editor-first4=Katie Ann |editor-first5=Elizabeth Arveda |editor-first6=Tomi-Ann |last1=Bobel |first1=C. |last2=Winkler |first2=I. T. |last3=Fahs |first3=B. |last4=Hasson |first4=K. A. |last5=Kissling |first5=E. A. |last6=Roberts |first6=T. A. }}
* {{cite book |author=Maria Kathryn Tomlinson |title=The Menstrual Movement in the Media |series=Palgrave Studies in Communication for Social Change |url=https://link.springer.com/book/10.1007/978-3-031-72195-3 |isbn=978-3-031-72195-3 |year=2025 |publisher=[[Springer Nature]]|doi=10.1007/978-3-031-72195-3 }}
* {{cite book |editor=Shackelford Todd K. |last1=Habeeb |first1=Saima |title=Encyclopedia of Sexual Psychology and Behavior |date=2023 |publisher=[[Springer, Cham]] |isbn=978-3-031-08956-5 |pages=1–11 |chapter-url=https://link.springer.com/referenceworkentry/10.1007/978-3-031-08956-5_1521-1 |language=en |chapter=Menstruation |doi=10.1007/978-3-031-08956-5_1521-1}}

== External links ==
* {{wikiquote-inline}}
* {{commons category-inline}}

{{Reproductive physiology}}
{{Menstrual cycle}}
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[[Category:Menstrual cycle]]
[[Category:Wikipedia medicine articles ready to translate]]
[[Category:Midwifery]]