A menstrual taboo is any social taboo concerned with menstruation. In some societies it involves menstruation being perceived as unclean or embarrassing, extending even to the mention of menstruation both in public (in the media and advertising) and in private (amongst the friends, in the household, and with men). Many traditional religions consider menstruation ritually unclean.
Different cultures view menstruation differently. Studies in the early 1980s have shown nearly all girls in the USA believed that girls should not talk about menstruation with boys, and more than one-third of the girls did not believe that it was appropriate to discuss menstruation with their fathers. The basis of many conduct norms and communication about menstruation in western industrial societies is the belief that menstruation should remain hidden.
In other societies certain menstrual taboos may be practised without the connotation of uncleanness. According to the anthropologists Buckley and Gottlieb cross-cultural study shows that, while taboos about menstruation are nearly universal, a wide range of distinct rules for conduct during menstruation "bespeak quite different, even opposite, purposes and meanings" with meanings that are "ambiguous and often multivalent".
In the Torah (Leviticus 15:19-30), a menstruating woman is considered ritually unclean - "anyone who touches her will be unclean until evening" (New International Version). Touching her, touching an object she had sat or lain on, and having intercourse with her also makes a person ritually unclean. The extent to which these rules are observed in modern Judaism varies depending on the degree of conservatism/orthodoxy.
Christians throughout history have disagreed about whether menstruation makes a woman unclean. In spite of the restrictions in Leviticus, Jesus allowed himself to be touched by a hemorrhaging woman and cured her (Mark 5:25-24). Some Church fathers defended the exclusion of women from ministry based on a notion of uncleanness.  Others held that purity laws should be discarded as part of the Old Covenant. There has never been any official teaching that menstruation makes women unclean in any major Christian denomination.
Bahá'u'lláh, the founder of the Bahá'í Faith, in the Kitáb-i-Aqdas abolished all forms of ritual impurity of people and things and stressed the importance of cleanliness and spiritual purity. Menstruating women are encouraged to pray and are not required to fast, they have the (voluntary) alternative of reciting a verse instead.
In Islam, a woman is not allowed to offer prayer or to perform other religious activities such as fasting or circumambulating the Kaaba, etc. This is in accordance with the law of the uncleanliness of any blood. Sexual intercourse with the husband is strictly prohibited during menstrual periods. However, she can perform all other acts of social life as normal. According to authentic traditions, Prophet Muhammad encouraged menstruating women to come to be present at festive religious services for the two Eid holidays even though they were excused from praying. Some scholars believe that the Muslim teachings of this taboo has fueled the prohibition of women as imams in the Muslim religion. They cite that Sharia Law has maintained this prohibition due to "ritual uncleanness."
In the Hindu faith, women are prohibited from participating in normal life while menstruating. She must be "purified" before she is allowed to return to her family, and this has been considered as a negative view of menstruation.
This follows a description in the Puranas about Indra's 'Brahmahatya' (act of killing of the Brahmin demon Vritra) and the mitigation of the sin. Part of this sin was taken by women, and is considered to be active during the menstrual period, therefore menstruating woman are forbidden from performing any rituals. Contact with menstruating woman is also forbidden (with exception of small children).
However in some respects Indians view menstruation, especially first menstruation or menarche, as a positive aspect of a girl's life. In South India and also in the Assamese community, girls who experience their menstrual period for the first time are given presents and celebrations to mark this special occasion, though women who are menstruating are not allowed in the household for a period of 3 nights. This certainly does not mean that they are driven away from the house during the cycle of their menstruation: according to Indian architecture, in a house with four blocks, 'dakkini' the south block, is for women and during the menstrual cycle women would confine themselves within this block, and would not even enter the kitchen or go to the north and east sides of the house, nor would they go near a temple.
But there is an exception to it in Kashmiri Hindu culture. The Kashmiri Pandits do not consider women as impure during menstrual cycle, instead they are given special care during this time as the body of the woman becomes weak due to blood loss. There is no such rule like a woman can not worship God or go to temple. The woman can indulge in all the household chores.
In Sikhism, a woman is given equal status to man and is regarded as pure as man is. The Gurus teach that one cannot be pure by washing his body but purity of mind is the real pureness. They are not called pure, who sit down after merely washing their bodies. Guru Nānak, the founder of Sikhism, condemned the practice of treating women as impure while menstruating.
In Sikhism, the menstrual cycle is not considered a pollutant. Certainly, it can have a physical and physiological effect on the woman. Nonetheless, this is not considered a hindrance to her wanting to pray or accomplish her religious duties fully. The Guru makes it very clear that the menstrual cycle is a God-given process. The blood of a woman is required for the creation of any human being. The requirement of the mother's blood is fundamental for life. Thus, the menstrual cycle is certainly an essential and God-given biological process. In other faiths blood is considered a pollutant. However, the Guru rejects such ideas. Those who are impure from within are the truly impure ones.
Meditating on God's name is of importance. Whether your clothes are blood-stained or not (including clothes stained from menstrual blood) is not of spiritual importance. Thus, there are no restrictions placed on a woman during her menstruation. She is free to visit a gurdwara, take part in prayers and do Seva. In The Feminine Principle in the Sikh: Vision of the Transcendent, Nikky Guninder Kaur-Singh writes: "The denigration of the female body 'expressed in many cultural and religious taboos surrounding menstruation and childbirth' is absent in the Sikh worldview. ... Guru Nanak openly chides those who attribute pollution to women because of menstruation."
In the USA
A survey conducted in 1981 showed that a substantial majority of U.S. adults and adolescents believed that it is socially unacceptable to discuss menstruation, especially in mixed company. Many believed that it is unacceptable to discuss menstruation even within the family.
One common way that even sanitary-product advertising avoids mentioning menstruation is by pouring a blue liquid on the sanitary product to demonstrate its absorptiveness. This shows the stigma surrounding the blood associated with menstruation. The invention of the tampon may have been inspired by the taboo, as tampons are more "discreet." Further evidence of the taboo is the creation of a variety of euphemisms for menstruation, including "Aunt Flo", "on the rag", "my friend", or even "the curse."
In 2010, Always created the first feminine hygiene ad to ever feature a tiny red spot, representing blood. The ad was created by an intern who was working at Always' advertising agency, Leo Burnett. Originally the ad was created for the intern's personal portfolio, but then it caught the attention of the Chief Creative Officer at Leo Burnett, and was subsequently published as an actual ad. There was some controversy when the ad was first released.
Movies and television also reflect the taboo nature of menstruation. Typically menstruation as a topic is avoided, except for scenes involving menarche or "first period." For example, as Elizabeth Arveda Kissling explains in her article, "On the Rag on Screen: Menarche in Film and Television," the early 1990s movie, My Girl contains a scene where the main character, Vada, experiences her first period. The explanation given to her by a female role model of what is happening to her is done off camera and the subject is never mentioned again, save when Vada pushes Thomas across the porch telling him, "Don't come back for five to seven days."
In the movie Carrie, the title character has her first period in the school gym shower, and the other girls tease her by throwing tampons and sanitary pads at her. The gym teacher, Miss Collins tries to calm Carrie down, and eventually must explain the concept of menstruation to Carrie (because Carrie's mother had never done so).
In Only Yesterday, one of the girls is found to be going through menstruation and is later teased about it, especially when a group of boys tell the others not to touch a ball she had touched by saying: "You'll catch her period".
Uta Pippig's 1996 Boston Marathon victory
In 1996, during the running of the 100th Boston Marathon, Uta Pippig, the first woman to cross the finish line, had visible blood and severe cramps. This was incorrectly attributed to menstruation. Commentators on radio and TV were, uncharacteristically, tongue-tied. ... "Physical problems and diarrhea," said some commentators. Others stopped at the phrase "physical problems", ... or "stomach pain" Eileen McNamara's Boston Globe article that said she "bled all the way from Hopkinton to Boston" was subject to mass criticism.
As Pippig recalls, "I started having stomach cramps about 5 miles into the race, and shortly after I had diarrhea. I was self-conscious [about it] not only for me — but in a caring way for our sport." She considered dropping out 7 or 8 miles in and even walked a little. Although uncomfortable, her focus shifted from winning the race to staying in it and running as well as she could in this situation. Later in the marathon, she admits "I was frightened when I felt blood flowing down my legs." That red trickle was widely attributed to menstrual problems, which Pippig says was a misconception. After winning the race, she was diagnosed with "ischemic colitis," or inflammatory bowel disease. 
With the recent FDA approval of menstrual suppression medications, researchers have begun to shift their focus to the attitudes of American women toward their periods. One study in particular found that 59% of the women they surveyed reported an interest in not menstruating every month. Of these 1/3 said they were interested in not menstruating at all anymore.
Overcoming this menstrual taboo is a point of contention amongst feminists. The primary argument behind this movement is that if menstruation is normal, there is no reason why the topic should be avoided: "After a while it becomes psychologically disorienting for women to look out at a world where their reality doesn't exist." Menstrual activism (also known as menarchy and radical menstruation) is a movement that addresses menstrual taboos.
- Culture and menstruation
- Grandmother hypothesis
- Menophilia, colloquially menstruation fetish.
- Arunachalam Muruganantham (subject of the 2013 documentary Menstrual Man).
- Williams, L. R. (1983). "Beliefs and Attitudes of Young Girls Regarding Menstruation". In Menarche, ed. Sharon Golub. Lexington, MA: Lexington.
- Laws, S. (1990). Issues of Blood: The Politics of Menstruation. London: Macmillan.
- Buckley, T., and Gottlieb, A., eds. (1988). Blood Magic: The Anthropology of Menstruation. Berkeley: University of California Press. (p. 7)
- "Women were considered ritually unclean".
- R. Hugh Connolly, [http://www.bombaxo.com/didascalia.html ''Didascalia Apostolorum'']. Oxford: Clarendon Press, 1929. Retrieved on 18 July 2013.
- Smith, Peter (2000). "purity". A concise encyclopedia of the Bahá'í Faith. Oxford: Oneworld Publications. pp. 281–282. ISBN 1-85168-184-1.
- Only they are pure, O Nanak, within whose minds the Lord abides. ||2|| (Siri Guru Granth Sahib Ji, Ang 472)
- "By coming together of mother and father are we created, By union of the mother's blood and the father's semen is the body made. To the Lord is the creature devoted, when hanging head downwards in the womb; He whom he contemplates, for him provides." (Guru Granth Sahib Ji, p.1013).
- "Should cloth be reckoned impure if blood-stained, How may minds of such be deemed pure, who suck the blood of mankind? Says Nanak: With a pure heart and tongue God's Name you utter: All else is worldly show, and false deeds." (Guru Granth Sahib Ji, pg. 140).
- Kaur-Singh, Nikky-Guninder (1993). The Feminine Principle in the Sikh Vision of the Transcendent. Cambridge University Press ISBN 0521432871. pp. 4.
- Research & Forecasts, Inc. (1981). "The Tampax Report: Summary of Survey Results on a Study of Attitudes towards Menstruation". New York: Research and Forecasts.
- Stampler, Laura (6 July 2011). "Bye, Bye Blue Liquid: Always Runs First Feminine Hygiene Ad To Show Blood". Huffington Post.
- Chyr, Willy. "How I Made The First Feminine Hygiene Ad To Ever Feature Blood". Jezebel.
- Kissling, Elizabeth Arveda (January 2006). "On the rag on screen: menarche in film and television". Sex Roles.
- Cahn, Susan; Jean O'Reilly, Susan K. Cahn. Women and Sports in the United States. pg 300. ISBN 1-55553-671-9.
- L.C. Andrist et al., LC; Arias, RD; Nucatola, D; Kaunitz, AM; Musselman, BL; Reiter, S; Boulanger, J; Dominguez, L et al. (2004). "Women's and providers' attitudes toward menstrual suppression with extended use of oral contraceptives". Contraception 70 (5): 359–363. doi:10.1016/j.contraception.2004.06.008. PMID 15504373.
- Houppert, Karen (1999). The Curse: Confronting the Last Unmentionable Taboo: Menstruation. New York: Farrar, Straus and Giroux. ISBN 0-374-27366-9.
- Cochrane, Kira (2 October 2009). "Women and women's interests, Health and wellbeing (Life and style), Life and style, Feminism (World news),World news". The Guardian (London).