Changes

'''Menstruation''' or '''menses''' occurs at the end of a [[placenta]]l [[mammal]]'s menstrual cycle. There are two types of menstruation:

'''Menstruation''' or '''menses''' occurs at the end of a [[placenta]]l [[mammal]]'s menstrual cycle. There are two types of menstruation:

* Overt menstruation, occuring in [[human]]s and [[great apes]], in which some of the lining of the [[uterus]] is shed and expelled from the body;

* Overt menstruation, occurring in [[human]]s and [[great apes]], in which some of the lining of the [[uterus]] is shed and expelled from the body;

* Covert menstruation, occuring in all other placental mammals, in which the [[endometrium]] is reabsorbed without being expelled.

* Covert menstruation, occurring in all other placental mammals, in which the [[endometrium]] is reabsorbed without being expelled.

 

Over the course of the menstrual cycle, the lining of the uterus builds up in preparation for implantation of a fertilized [[ovum]].  If no conception occurs, the thickened lining is sloughed off and flows out though the cervix and vaginal canal.  The process of thickening then starts again for the next menstrual cycle.<ref>[http://www.4woman.gov/faq/menstru.htm#4 Menstruation and the Menstrual Cycle, from the US Dept. of Health and Human Services]</ref> If conception occurs, hormonal changes occur in the body that prevent menstruation from occurring.

Over the course of the menstrual cycle, the lining of the uterus builds up in preparation for implantation of a fertilized [[ovum]].  If no conception occurs, the thickened lining is sloughed off and flows out though the cervix and vaginal canal.  The process of thickening then starts again for the next menstrual cycle.<ref>[http://www.4woman.gov/faq/menstru.htm#4 Menstruation and the Menstrual Cycle, from the US Dept. of Health and Human Services]</ref> If conception occurs, hormonal changes occur in the body that prevent menstruation from occurring.

A number of hypotheses have been put forth regarding the purpose or benefit of menstruation:

A number of hypotheses have been put forth regarding the purpose or benefit of menstruation:

* The ancient physician [[Hippocrates]] held that menstruation was the body's means of purging itself of bad [[humor]]s, based on his belief that an excess of blood in the body led to health problems;

* The ancient physician [[Hippocrates]] held that menstruation was the body's means of purging itself of bad [[humor]]s, based on his belief that an excess of blood in the body led to health problems;

* Margie Profet argues that menstruaction was the body's means of purging the uterus and reproductive system of bacterial infection, based on the fact that menstrual blood contains an unusually large amount of macrophages, or immune cells <ref>http://www.ncbi.nlm.nih.gov/pubmed/8210311</ref>;

* Margie Profet argues that menstruation was the body's means of purging the uterus and reproductive system of bacterial infection, based on the fact that menstrual blood contains an unusually large amount of macrophages, or immune cells <ref>http://www.ncbi.nlm.nih.gov/pubmed/8210311</ref>;

* Beverly Strassmann argued that the purpose of menstruation is energy conservation -- that the endometrium is very energy-intensive, so it is more efficient to maintain it for only part of the time.  "Endometrial economy," she argued, preserves the metabolic equivalent of six days worth of food for women.<ref>Strassmann, Beverly I. (1996) "The Evolution of Endometrial Cycles and Menstruation", Quarterly Review of Biology 71, 2(June): 181-221. </ref>

* Beverly Strassmann argued that the purpose of menstruation is energy conservation -- that the endometrium is very energy-intensive, so it is more efficient to maintain it for only part of the time.  "Endometrial economy," she argued, preserves the metabolic equivalent of six days worth of food for women.<ref>Strassmann, Beverly I. (1996) "The Evolution of Endometrial Cycles and Menstruation", Quarterly Review of Biology 71, 2(June): 181-221. </ref>

* Elsimar M. Coutinho argues that menstruation acted as a sign that a woman had failed to conceive in the past, and as such is now "obsolete" and should be "cured" by modern medicine.  <ref>Elsimar M. Coutinho, ''Is Menstruation Obsolete?''</ref>

* Elsimar M. Coutinho argues that menstruation acted as a sign that a woman had failed to conceive in the past, and as such is now "obsolete" and should be "cured" by modern medicine.  <ref>Elsimar M. Coutinho, ''Is Menstruation Obsolete?''</ref>

Max Neuberger, writing in his "History of Medicine" states:

Max Neuberger, writing in his "History of Medicine" states:

{{cquote|The commands concern prophylaxis and suppression of epidemics, suppression of venereal disease and prostitution, care of the skin, baths, food, housing and clothing, regulation of labour, sexual life, discipline of the people, etc. Many of these commands, such as Sabbath rest, circumcision, laws concerning food (interdiction of blood and pork), measures concerning menstruating and lying-in women, and those suffering from gonorrhoea, isolation of lepers, and hygiene of the camp, are, in view of the conditions of the climate, surprisingly rational.<ref name=Neuberger>Neuburger, Max. ''History of Medicine''. Oxford University Press, 1910, Vol. I, p. 38.</ref>}}

{{cquote|The commands concern prophylaxis and suppression of epidemics, suppression of venereal disease and prostitution, care of the skin, baths, food, housing and clothing, regulation of labour, sexual life, discipline of the people, etc. Many of these commands, such as Sabbath rest, circumcision, laws concerning food (interdiction of blood and pork), measures concerning menstruating and lying-in women, and those suffering from gonorrhea, isolation of lepers, and hygiene of the camp, are, in view of the conditions of the climate, surprisingly rational.<ref name=Neuberger>Neuburger, Max. ''History of Medicine''. Oxford University Press, 1910, Vol. I, p. 38.</ref>}}

An abstract for the L.L. Ben-Noun 2003 article in the ''European Journal of Obstetrics, Gynecology, and Reproductive Biology'' entitled "What is the biblical attitude towards personal hygiene during vaginal bleeding?" states the following:  

An abstract for the L.L. Ben-Noun 2003 article in the ''European Journal of Obstetrics, Gynecology, and Reproductive Biology'' entitled "What is the biblical attitude towards personal hygiene during vaginal bleeding?" states the following:  

==References==

==References==

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[[Category:Biology]]

[[Category:Biology]]

[[Category:Human Development]]

[[Category:Human Development]]