Editing Vagina (section)

==Function==
===Secretions===
{{Main|Vaginal discharge|Vaginal lubrication}}
Vaginal secretions are primarily from the [[uterus]], cervix, and vaginal epithelium in addition to minuscule [[vaginal lubrication]] from the [[Bartholin's gland]]s upon sexual arousal.<ref name="Dutta"/> It takes little vaginal secretion to make the vagina moist; secretions may increase during sexual arousal, the middle of or a little prior to [[menstruation]], or during [[pregnancy]].<ref name="Dutta"/> Menstruation (also known as a "period" or "monthly") is the regular discharge of blood and mucosal tissue (known as menses) from the [[endometrium|inner lining of the uterus]] through the vagina.<ref name=Women2014Men>{{cite web|title=Menstruation and the menstrual cycle fact sheet|url=http://www.womenshealth.gov/publications/our-publications/fact-sheet/menstruation.html|website=Office of Women's Health|access-date=June 25, 2015|date=December 23, 2014|url-status=dead|archive-url=https://web.archive.org/web/20150626134338/http://www.womenshealth.gov/publications/our-publications/fact-sheet/menstruation.html|archive-date=June 26, 2015}}</ref> The vaginal mucous membrane varies in thickness and composition during the [[menstrual cycle]],<ref>{{Cite book |vauthors=Wangikar P, Ahmed T, Vangala S |chapter=Toxicologic pathology of the reproductive system |title=Reproductive and developmental toxicology |veditors=Gupta RC |date=2011 |publisher=Academic Press |isbn=978-0-12-382032-7 |location=London |page=1005 |oclc=717387050}}</ref> which is the regular, natural change that occurs in the [[female reproductive system]] (specifically the uterus and [[ovary|ovaries]]) that makes pregnancy possible.<ref name=Silverthorn>{{cite book|vauthors=Silverthorn DU|title = Human Physiology: An Integrated Approach |edition=6th |publisher = Pearson Education |location = Glenview, IL |year = 2013 | isbn = 978-0-321-75007-5 |pages=850–890}}</ref><ref name=Sherwood>{{cite book|vauthors=Sherwood L |title = Human Physiology: From Cells to Systems | edition=8th |publisher = Cengage |location = Belmont, California | year = 2013 |isbn = 978-1-111-57743-8 |pages=735–794}}</ref> Different [[feminine hygiene|hygiene products]] such as [[tampon]]s, [[menstrual cup]]s, and [[sanitary napkin]]s are available to absorb or capture menstrual blood.<ref name="Vostral">{{cite book|vauthors=Vostral SL|title=Under Wraps: A History of Menstrual Hygiene Technology|publisher=[[Lexington Books]]|isbn=978-0-7391-1385-1|year=2008|pages=1–181|url=https://books.google.com/books?id=PWA0yisYPnEC|access-date=March 22, 2018|archive-date=March 10, 2021|archive-url=https://web.archive.org/web/20210310000252/https://books.google.com/books?id=PWA0yisYPnEC|url-status=live}}</ref>

The Bartholin's glands, located near the vaginal opening, were originally considered the primary source for vaginal lubrication, but further examination showed that they provide only a few drops of [[mucus]].<ref name="Sloane">{{cite book|vauthors=Sloane E|title=Biology of Women|url=https://books.google.com/books?id=kqcYyk7zlHYC&pg=PA32|year=2002|publisher=[[Cengage Learning]]|isbn=978-0-7668-1142-3|pages=32, 41–42|access-date=October 27, 2015|archive-date=June 28, 2014|archive-url=https://web.archive.org/web/20140628044307/http://books.google.com/books?id=kqcYyk7zlHYC&pg=PA32|url-status=live}}</ref> Vaginal lubrication is mostly provided by plasma seepage known as [[transudate]] from the vaginal walls. This initially forms as sweat-like droplets, and is caused by increased fluid pressure in the tissue of the vagina ([[vasocongestion]]), resulting in the release of plasma as transudate from the [[capillary|capillaries]] through the vaginal epithelium.<ref name="Sloane"/><ref name="Bourcier">{{cite book|vauthors=Bourcier A, McGuire EJ, Abrams P|title=Pelvic Floor Disorders|url=https://books.google.com/books?id=4sO5a7R1NNwC&pg=PA20|year=2004|publisher=[[Elsevier Health Sciences]]|isbn=978-0-7216-9194-7|page=20|access-date=June 8, 2018|archive-date=July 4, 2019|archive-url=https://web.archive.org/web/20190704044806/https://books.google.com/books?id=4sO5a7R1NNwC&pg=PA20|url-status=live}}</ref><ref name="Wiederman">{{cite book|vauthors=Wiederman MW, Whitley BE Jr|title=Handbook for Conducting Research on Human Sexuality|url=https://books.google.com/books?id=L6c11oy8PGMC&q=transudation|date=2012|publisher=[[Psychology Press]]|isbn=978-1-135-66340-7|access-date=June 8, 2018|archive-date=July 4, 2019|archive-url=https://web.archive.org/web/20190704044837/https://books.google.com/books?id=L6c11oy8PGMC&q=transudation|url-status=live}}</ref>

Before and during [[ovulation]], the mucous glands within the cervix secrete different variations of mucus, which provides an [[Alkalinity|alkaline]], [[fertile]] environment in the vaginal canal that is favorable to the survival of [[sperm]].<ref name="Cummings">{{cite book |vauthors=Cummings M |title=Human Heredity: Principles and Issues |edition=Updated |publisher=[[Cengage Learning]] |isbn=978-0-495-11308-9 |year=2006 |pages=153–154 |url=https://books.google.com/books?id=Gq06QUuNTugC&pg=PT185 |access-date=October 27, 2015 |archive-date=May 6, 2016 |archive-url=https://web.archive.org/web/20160506171032/https://books.google.com/books?id=Gq06QUuNTugC&pg=PT185 |url-status=live }}</ref> Following menopause, vaginal lubrication naturally decreases.<ref name="Sirven">{{cite book|vauthors=Sirven JI, Malamut BL|title=Clinical Neurology of the Older Adult|publisher=[[Lippincott Williams & Wilkins]]|isbn=978-0-7817-6947-1|year=2008|pages=230–232|url=https://books.google.com/books?id=c1tL8C9ryMQC&pg=PA230|access-date=June 8, 2018|archive-date=July 3, 2019|archive-url=https://web.archive.org/web/20190703211321/https://books.google.com/books?id=c1tL8C9ryMQC&pg=PA230|url-status=live}}</ref>

=== Sexual stimulation ===
{{further|Human sexual activity|Human female sexuality}}
Nerve endings in the vagina can provide pleasurable sensations when the vagina is stimulated during sexual activity. Women may derive pleasure from one part of the vagina, or from a feeling of closeness and fullness during vaginal penetration.<ref name="Tara Lee">{{cite book|vauthors=Lee MT|title=Love, Sex and Everything in Between|publisher=[[Marshall Cavendish|Marshall Cavendish International Asia Pte Ltd]]|year=2013|page=76|isbn=978-981-4516-78-5|url=https://books.google.com/books?id=fnRMAgAAQBAJ&pg=PT76|access-date=October 27, 2015|archive-date=May 6, 2016|archive-url=https://web.archive.org/web/20160506155534/https://books.google.com/books?id=fnRMAgAAQBAJ&pg=PT76|url-status=live}}</ref> Because the vagina is not rich in nerve endings, women often do not receive sufficient sexual stimulation, or [[orgasm]], solely from vaginal penetration.<ref name="Tara Lee"/><ref name="Sex and Society">{{cite book|title=Sex and Society|volume=2|isbn=978-0-7614-7907-9|publisher=[[Marshall Cavendish Corporation]]|year=2009|page=590|url=https://books.google.com/books?id=YtsxeWE7VD0C&pg=PA590|access-date=August 20, 2020|archive-date=April 12, 2021|archive-url=https://web.archive.org/web/20210412102723/https://books.google.com/books?id=YtsxeWE7VD0C&pg=PA590|url-status=live}}</ref><ref name="Weiten">{{cite book|vauthors=Weiten W, Dunn D, Hammer E|title=Psychology Applied to Modern Life: Adjustment in the 21st Century|url=https://books.google.com/books?id=CGu96TeAZo0C&pg=PT423|date=2011|publisher=[[Cengage Learning]]|isbn=978-1-111-18663-0|page=386|access-date=October 27, 2015|archive-date=June 14, 2013|archive-url=https://web.archive.org/web/20130614031527/http://books.google.com/books?id=CGu96TeAZo0C&pg=PT423|url-status=live}}</ref> Although the literature commonly cites a greater concentration of nerve endings and therefore greater sensitivity near the vaginal entrance (the outer one-third or lower third),<ref name="Sex and Society"/><ref name="Weiten"/><ref name="Greenberg2">{{cite book|vauthors=Greenberg JS, Bruess CE, Conklin SC|title=Exploring the Dimensions of Human Sexuality|publisher=[[Jones & Bartlett Publishers]]|year=2010|page=126|isbn=978-981-4516-78-5|url=https://books.google.com/books?id=5Sy8PJZGyWUC&pg=PA126|access-date=October 27, 2015|archive-date=May 2, 2016|archive-url=https://web.archive.org/web/20160502022058/https://books.google.com/books?id=5Sy8PJZGyWUC&pg=PA126|url-status=live}}</ref> some scientific examinations of vaginal wall innervation indicate no single area with a greater density of nerve endings.<ref name="Greenberg">{{cite book|vauthors=Greenberg JS, Bruess CE, Oswalt SB|title=Exploring the Dimensions of Human Sexuality|pages=102–104|isbn=978-1-4496-4851-0|date=2014|publisher=[[Jones & Bartlett Publishers]]|url=https://books.google.com/books?id=hm3aTuANFroC&pg=PA102|access-date=October 27, 2015|archive-date=September 10, 2015|archive-url=https://web.archive.org/web/20150910150644/https://books.google.com/books?id=hm3aTuANFroC&pg=PA102|url-status=live}}</ref><ref name="Hines">{{cite journal |vauthors=Hines T |s2cid=32381437 |date=August 2001 |title=The G-Spot: A modern gynecologic myth |journal=Am J Obstet Gynecol |volume=185 |issue=2 |pages=359–62 |doi=10.1067/mob.2001.115995 |pmid=11518892 }}{{Dead link|date=August 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> Other research indicates that only some women have a greater density of nerve endings in the anterior vaginal wall.<ref name="Greenberg"/><ref name="Bullough">{{cite book|vauthors=Bullough VL, Bullough B|title=Human Sexuality: An Encyclopedia|publisher=[[Routledge]]|year=2014|pages=229–231|isbn=978-1-135-82509-6|url=https://books.google.com/books?id=UHymAgAAQBAJ&pg=PA229|access-date=October 27, 2015|archive-date=May 6, 2016|archive-url=https://web.archive.org/web/20160506163017/https://books.google.com/books?id=UHymAgAAQBAJ&pg=PA229|url-status=live}}</ref> Because of the fewer nerve endings in the vagina, childbirth pain is significantly more tolerable.<ref name="Weiten"/><ref name="Balon, Segraves">{{cite book |vauthors=Balon R, Segraves RT |title=Clinical Manual of Sexual Disorders |publisher=[[American Psychiatric Association|American Psychiatric Pub]] |year=2009 |page=258 |isbn=978-1-58562-905-3 |url=https://books.google.com/books?id=YuP3Hb0TMLQC&pg=PA258 |access-date=October 27, 2015 |archive-date=June 27, 2014 |archive-url=https://web.archive.org/web/20140627021747/http://books.google.com/books?id=YuP3Hb0TMLQC&pg=PA258 |url-status=live }}</ref><ref name="Rosenthal">{{cite book|vauthors=Rosenthal M|title=Human Sexuality: From Cells to Society|url=https://books.google.com/books?id=d58z5hgQ2gsC&pg=PT96|date=2012|publisher=[[Cengage Learning]]|isbn=978-0-618-75571-4|page=76|access-date=October 27, 2015|archive-date=December 10, 2020|archive-url=https://web.archive.org/web/20201210125644/https://books.google.com/books?id=d58z5hgQ2gsC&pg=PT96|url-status=live}}</ref>

Pleasure can be derived from the vagina in a variety of ways. In addition to [[Human penis|penile]] penetration, pleasure can come from [[masturbation]], [[Fingering (sexual act)|fingering]], or specific [[sex position]]s (such as the [[missionary position]] or the [[spoons sex position]]).<ref name="Carroll 0">{{cite book|vauthors=Carroll J|title=Discovery Series: Human Sexuality|publisher=[[Cengage Learning]]|year=2012|pages=282–289|isbn=978-1-111-84189-8|url=https://books.google.com/books?id=gU3SZSh-eXsC&pg=PT313|access-date=October 27, 2015|archive-date=May 5, 2016|archive-url=https://web.archive.org/web/20160505002653/https://books.google.com/books?id=gU3SZSh-eXsC&pg=PT313|url-status=live}}</ref> Heterosexual couples may engage in fingering as a form of [[foreplay]] to incite sexual arousal or as an accompanying act,<ref name="Carroll 1">{{cite book|vauthors=Carroll JL|title=Sexuality Now: Embracing Diversity|edition=1st|publisher=[[Cengage Learning]]|year=2018|page=299|isbn=978-1-337-67206-1|url=https://books.google.com/books?id=9A9EDwAAQBAJ&pg=PT299|access-date=January 16, 2018|archive-date=July 3, 2019|archive-url=https://web.archive.org/web/20190703211235/https://books.google.com/books?id=9A9EDwAAQBAJ&pg=PT299|url-status=live}}</ref><ref name="Hales 0">{{cite book|vauthors=Hales D|title=An Invitation to Health|edition=1st|publisher=[[Cengage Learning]]|year=2012|pages=296–297|isbn=978-1-111-82700-7|url=https://books.google.com/books?id=t_B1GzgHEMkC&pg=PT317|access-date=January 16, 2018|archive-date=July 3, 2019|archive-url=https://web.archive.org/web/20190703211235/https://books.google.com/books?id=t_B1GzgHEMkC&pg=PT317|url-status=live}}</ref> or as a type of [[birth control]], or to [[Virginity#Definitions of virginity loss|preserve virginity]].<ref name="Intimate">{{Cite book|vauthors=Strong B, DeVault C, Cohen TF|title=The Marriage and Family Experience: Intimate Relationship in a Changing Society|publisher=[[Cengage Learning]]|year=2010|page=186|isbn=978-0-534-62425-5|url=https://books.google.com/books?id=qjvoSOMB5JMC&pg=PA186|quote=Most people agree that we maintain virginity as long as we refrain from sexual (vaginal) intercourse. But occasionally we hear people speak of 'technical virginity' [...] Data indicate that 'a very significant proportion of teens ha[ve] had experience with oral sex, even if they haven't had sexual intercourse, and may think of themselves as virgins' [...] Other research, especially research looking into virginity loss, reports that 35% of virgins, defined as people who have never engaged in vaginal intercourse, have nonetheless engaged in one or more other forms of heterosexual sexual activity (e.g., oral sex, anal sex, or mutual masturbation).|access-date=August 20, 2020|archive-date=July 24, 2020|archive-url=https://web.archive.org/web/20200724205226/https://books.google.com/books?id=qjvoSOMB5JMC&pg=PA186|url-status=live}}</ref><ref name="Rosenthal 2">See [https://books.google.com/books?id=d58z5hgQ2gsC&pg=PT290 272] {{Webarchive|url=https://web.archive.org/web/20160501140819/https://books.google.com/books?id=d58z5hgQ2gsC&pg=PT290 |date=May 1, 2016 }} and [https://books.google.com/books?id=d58z5hgQ2gsC&pg=PT321 page 301] {{Webarchive|url=https://web.archive.org/web/20160507064706/https://books.google.com/books?id=d58z5hgQ2gsC&pg=PT321 |date=May 7, 2016 }} for two different definitions of outercourse (first of the pages for no-penetration definition; second of the pages for no-penile-penetration definition). {{cite book |vauthors=Rosenthal M |title=Human Sexuality: From Cells to Society |edition=1st |publisher=[[Cengage Learning]] |year=2012 |isbn=978-0-618-75571-4 |url=https://books.google.com/books?id=d58z5hgQ2gsC |access-date=October 2, 2015 |archive-date=September 30, 2015 |archive-url=https://web.archive.org/web/20150930220034/https://books.google.com/books?id=d58z5hgQ2gsC |url-status=live }}</ref> Less commonly, they may use non penile-vaginal sexual acts as a primary means of sexual pleasure.<ref name="Hales 0"/> In contrast, [[lesbian]]s and other [[women who have sex with women]] commonly engage in fingering as a [[Lesbian sexual practices|main form of sexual activity]].<ref name="Carroll 3">{{cite book|title=Sexuality Now: Embracing Diversity|isbn=978-0-495-60274-3|publisher=Cengage Learning|year=2009|page=272|url=https://books.google.com/books?id=5f8mQx7ULs4C&pg=PA272|vauthors=Carroll JL|access-date=August 20, 2020|archive-date=June 15, 2013|archive-url=https://web.archive.org/web/20130615013659/http://books.google.com/books?id=5f8mQx7ULs4C&pg=PA272|url-status=live}}</ref><ref name="Zenilman & Shahmanesh">{{cite book | title = Sexually Transmitted Infections: Diagnosis, Management, and Treatment | publisher = [[Jones & Bartlett Learning|Jones & Bartlett Publishers]] | year = 2011 | pages = 329–330 | isbn = 978-0-495-81294-4 | url = https://books.google.com/books?id=lO5BND02eBwC&pg=PA329 | vauthors = Zenilman J, Shahmanesh M | access-date = August 20, 2020 | archive-date = March 12, 2017 | archive-url = https://web.archive.org/web/20170312224711/https://books.google.com/books?id=lO5BND02eBwC&pg=PA329 | url-status = live }}</ref> Some women and couples use [[sex toys]], such as a [[Vibrator (sex toy)|vibrator]] or [[dildo]], for vaginal pleasure.<ref name="Taormino">{{cite book|vauthors=[[Tristan Taormino|Taormino T]]|title=The Big Book of Sex Toys|publisher=Quiver|year=2009|page=52|isbn=978-1-59233-355-4|url=https://books.google.com/books?id=Hfly-iMkWRkC&pg=PA52|access-date=October 27, 2015|archive-date=September 5, 2015|archive-url=https://web.archive.org/web/20150905081729/https://books.google.com/books?id=Hfly-iMkWRkC&pg=PA52|url-status=live}}</ref>

Most women require direct stimulation of the [[clitoris]] to orgasm.<ref name="Sex and Society"/><ref name="Weiten"/> The clitoris plays a part in vaginal stimulation. It is a sex organ of multiplanar structure containing an abundance of nerve endings, with a broad attachment to the pubic arch and extensive supporting tissue to the labia. Research indicates that it forms a tissue cluster with the vagina. This tissue is perhaps more extensive in some women than in others, which may contribute to orgasms experienced vaginally.<ref name="Sex and Society"/><ref name="O'Connell">{{cite journal |vauthors=O'Connell HE, Sanjeevan KV, Hutson JM |s2cid=26109805 |title=Anatomy of the clitoris |journal=The Journal of Urology |volume=174 |issue=4 Pt 1 |pages=1189–95 |date=October 2005 |pmid=16145367 |doi=10.1097/01.ju.0000173639.38898.cd}}
*{{cite news |author=Sharon Mascall |date=June 11, 2006 |title=Time for rethink on the clitoris |work=[[BBC News]] |url=http://news.bbc.co.uk/2/hi/health/5013866.stm}}</ref><ref name="Kilchevsky">{{cite journal |title=Is the Female G-Spot Truly a Distinct Anatomic Entity? |journal=[[The Journal of Sexual Medicine]] |volume=9 |date=January 2012 |pmid=22240236 |doi=10.1111/j.1743-6109.2011.02623.x|vauthors=Kilchevsky A, Vardi Y, Lowenstein L, Gruenwald I |issue=3 |pages=719–26}}
*{{cite news |date=January 19, 2012 |title=G-Spot Does Not Exist, 'Without A Doubt,' Say Researchers |work=[[The Huffington Post]] |url=http://www.huffingtonpost.com/2012/01/19/g-spot-does-not-exist_n_1215822.html}}</ref>

During sexual arousal, and particularly the stimulation of the clitoris, the walls of the vagina lubricate. This begins after ten to thirty seconds of sexual arousal, and increases in amount the longer the woman is aroused.<ref name="Heffner">{{cite book|vauthors=Heffner LJ, Schust DJ|title=The Reproductive System at a Glance|page=39|isbn=978-1-118-60701-5|date=2014|publisher=[[John Wiley & Sons]]|url=https://books.google.com/books?id=JuvcAgAAQBAJ&pg=PA39|access-date=October 27, 2015|archive-date=April 28, 2016|archive-url=https://web.archive.org/web/20160428170307/https://books.google.com/books?id=JuvcAgAAQBAJ&pg=PA39|url-status=live}}</ref> It reduces friction or injury that can be caused by insertion of the penis into the vagina or other penetration of the vagina during sexual activity. The vagina lengthens during the arousal, and can continue to lengthen in response to pressure; as the woman becomes fully aroused, the vagina expands in length and width, while the cervix retracts.<ref name="Heffner"/><ref name="Silbernagl">{{cite book|vauthors=Silbernagl S, Despopoulos A|title=Color Atlas of Physiology|publisher=[[Thieme Medical Publishers|Thieme]]|page=310|isbn=978-1-4496-4851-0|date=2011|url=https://books.google.com/books?id=WyuCGhv4kvwC&pg=PA310|access-date=October 27, 2015|archive-date=May 7, 2016|archive-url=https://web.archive.org/web/20160507064443/https://books.google.com/books?id=WyuCGhv4kvwC&pg=PA310|url-status=live}}</ref> With the upper two-thirds of the vagina expanding and lengthening, the uterus rises into the [[greater pelvis]], and the cervix is elevated above the vaginal floor, resulting in tenting of the mid-vaginal plane.<ref name="Heffner"/> This is known as the tenting or ballooning effect.<ref name="Carroll 2">{{cite book|vauthors=Carroll JL|title=Sexuality Now: Embracing Diversity|publisher=[[Cengage Learning]]|page=271|isbn=978-1-305-44603-8|date=2015|url=https://books.google.com/books?id=cy9-BAAAQBAJ&pg=PT271|access-date=August 21, 2017|archive-date=July 4, 2019|archive-url=https://web.archive.org/web/20190704044828/https://books.google.com/books?id=cy9-BAAAQBAJ&pg=PT271|url-status=live}}</ref>  As the elastic walls of the vagina [[Vaginal contraction|stretch or contract]], with support from the pelvic muscles, to wrap around the inserted penis (or other object),<ref name="Greenberg2"/> this creates friction for the penis and helps to cause a man to experience orgasm and [[ejaculation]], which in turn enables [[Human fertilization|fertilization]].<ref name="Publishing">{{cite book|vauthors=Brewster S, Bhattacharya S, Davies J, Meredith S, Preston P|title=The Pregnant Body Book|publisher=[[Penguin Books|Penguin]]|pages=66–67|isbn=978-0-7566-8712-0|date=2011|url=https://books.google.com/books?id=yBIuIN40JaQC&pg=PA66|access-date=March 4, 2015|archive-date=May 15, 2015|archive-url=https://web.archive.org/web/20150515122827/https://books.google.com/books?id=yBIuIN40JaQC&pg=PA66|url-status=live}}</ref>

An area in the vagina that may be an [[erogenous zone]] is the [[G-spot]]. It is typically defined as being located at the anterior wall of the vagina, a couple or few inches in from the entrance, and some women experience intense pleasure, and sometimes an orgasm, if this area is stimulated during sexual activity.<ref name="Greenberg"/><ref name="Bullough"/> A G-spot orgasm may be responsible for [[female ejaculation]], leading some doctors and researchers to believe that G-spot pleasure comes from the [[Skene's gland]]s, a female [[Homology (biology)|homologue]] of the [[prostate]], rather than any particular spot on the vaginal wall; other researchers consider the connection between the Skene's glands and the G-spot area to be weak.<ref name="Greenberg"/><ref name="Hines"/><ref name="Bullough"/> The G-spot's existence (and existence as a distinct structure) is still under dispute because reports of its location can vary from woman to woman, it appears to be nonexistent in some women, and it is hypothesized to be an extension of the clitoris and therefore the reason for orgasms experienced vaginally.<ref name="Greenberg"/><ref name="Balon, Segraves"/><ref name="Kilchevsky"/>

===Childbirth===
{{Main|Childbirth}}
The vagina is the birth canal for the [[vaginal delivery|delivery]] of a baby. When labor nears, several signs may occur, including vaginal discharge and the [[rupture of membranes]] (water breaking). The latter results in a gush or small stream of [[amniotic fluid]] from the vagina.<ref name=Linnard-Palmer2017>{{Cite book|last1=Linnard-Palmer|first1=Luanne|last2=Coats|first2=Gloria|title=Safe Maternity and Pediatric Nursing Care|publisher=[[F. A. Davis Company]]|year=2017|isbn=978-0-8036-2494-8|page=108|language=en}}</ref> Water breaking most commonly happens at the beginning of labor. It happens before labor if there is a [[premature rupture of membranes]], which occurs in 10% of cases.<ref name="Callahan">{{cite book|vauthors=Callahan T, Caughey AB|title=Blueprints Obstetrics and Gynecology|publisher=[[Lippincott Williams & Wilkins]]|isbn=978-1-4511-1702-8|year=2013|page=40|url=https://books.google.com/books?id=eKC1B3BhlxUC&pg=PA40|access-date=January 8, 2018|archive-date=July 3, 2019|archive-url=https://web.archive.org/web/20190703215955/https://books.google.com/books?id=eKC1B3BhlxUC&pg=PA40|url-status=live}}</ref> Among women giving birth for the first time, [[Braxton Hicks contractions]] are mistaken for actual [[Uterine contraction#Childbirth|contractions]],<ref name="Pillitteri">{{cite book|vauthors=Pillitteri A|title=Maternal and Child Health Nursing: Care of the Childbearing and Childrearing Family|publisher=[[Lippincott Williams & Wilkins]]|isbn=978-1-4698-3322-4|year=2013|page=298|url=https://books.google.com/books?id=26idAgAAQBAJ&pg=PA298|access-date=January 3, 2018|archive-date=July 3, 2019|archive-url=https://web.archive.org/web/20190703211312/https://books.google.com/books?id=26idAgAAQBAJ&pg=PA298|url-status=live}}</ref> but they are instead a way for the body to prepare for true labor. They do not signal the beginning of labor,<ref name=Raines2021>{{Cite book|last1=Raines|first1=Deborah|last2=Cooper|first2=Danielle B.|url=https://www.ncbi.nlm.nih.gov/books/NBK470546/|title=Braxton Hicks Contractions|publisher=StatPearls Publishing|year=2021|pmid=29262073|language=en}}</ref> but they are usually very strong in the days leading up to labor.<ref name="Pillitteri"/><ref name=Raines2021/>

As the body prepares for childbirth, the cervix softens, [[Cervical effacement|thins]], moves forward to face the front, and begins to open. This allows the fetus to settle into the pelvis, a process known as lightening.<ref name=Forbes2020>{{Cite book|last1=Forbes|first1=Helen|last2=Watt|first2=Elizabethl|url=https://www.elsevier.com/books/jarviss-health-assessment-and-physical-examination/forbes/978-0-7295-4337-8|title=Jarvis's Health Assessment and Physical Examination|publisher=[[Elsevier Health Sciences]]|year=2020|isbn=978-0-729-58793-8|edition=3|page=834|language=en}}</ref> As the fetus settles into the pelvis, pain from the [[sciatic nerve]]s, increased vaginal discharge, and increased urinary frequency can occur.<ref name=Forbes2020/> While lightening is likelier to happen after labor has begun for women who have given birth before, it may happen ten to fourteen days before labor in women experiencing labor for the first time.<ref name="Orshan">{{cite book|vauthors=Orshan SA |title=Maternity, Newborn, and Women's Health Nursing: Comprehensive Care Across the Lifespan|publisher=[[Lippincott Williams & Wilkins]]|isbn=978-0-7817-4254-2|year=2008|pages=[https://archive.org/details/maternitynewborn0000orsh/page/585 585]–586 |url=https://archive.org/details/maternitynewborn0000orsh|url-access=registration }}</ref>

The fetus begins to lose the support of the cervix when contractions begin. With [[cervical dilation]] reaching 10&nbsp;cm to accommodate the head of the fetus, the head moves from the uterus to the vagina.<ref name=Linnard-Palmer2017/><ref name=Hutchison2022>{{Cite book|last1=Hutchison|first1=Julia|last2=Mahdy|first2=Heba|last3=Hutchison|first3=Justin|url=https://www.ncbi.nlm.nih.gov/books/NBK544290/|title=Stages of Labor |chapter=Normal Labor: Physiology, Evaluation, and Management |publisher=StatPearls Publishing|year=2022|pmid=31335010|language=en}}</ref> The elasticity of the vagina allows it to stretch to many times its normal diameter in order to deliver the child.<ref>{{Cite journal|last1=Clark–Patterson|first1=Gabrielle|last2=Domingo|first2=Mari|last3=Miller|first3=Kristin|date= June 2022|title=Biomechanics of pregnancy and vaginal delivery|journal=Current Opinion in Biomedical Engineering|volume=22|page=100386 |doi=10.1016/j.cobme.2022.100386|s2cid=247811789 |issn=2468-4511|doi-access=free}}</ref>

Vaginal births are more common, but if there is a risk of complications a [[caesarean section]] (C-section) may be performed.<ref name=NIH>{{cite web|title=Pregnancy Labor and Birth|url=https://www.womenshealth.gov/pregnancy/childbirth-and-beyond/labor-and-birth|publisher=Office on Women's Health, U.S. Department of Health and Human Services|access-date=July 15, 2017|date=February 1, 2017|url-status=live|archive-url=https://web.archive.org/web/20170728021055/https://www.womenshealth.gov/pregnancy/childbirth-and-beyond/labor-and-birth|archive-date=July 28, 2017}}</ref> The vaginal mucosa has an abnormal accumulation of fluid ([[edematous]]) and is thin, with few rugae, a little after birth. The mucosa thickens and rugae return in approximately three weeks once the ovaries regain usual function and estrogen flow is restored. The vaginal opening gapes and is relaxed, until it returns to its approximate pre-pregnant state six to eight weeks after delivery, known as the [[postpartum period]]; however, the vagina will continue to be larger in size than it was previously.<ref name="Ricci">{{cite book |vauthors=Ricci SS, Kyle T |title=Maternity and Pediatric Nursing|publisher=[[Lippincott Williams & Wilkins]]|isbn=978-0-7817-8055-1|year=2009|pages=[https://archive.org/details/maternitypediatr0000ricc/page/431 431]–432 |url=https://archive.org/details/maternitypediatr0000ricc|url-access=registration }}</ref>

After giving birth, there is a phase of vaginal discharge called [[lochia]] that can vary significantly in the amount of loss and its duration but can go on for up to six weeks.<ref name="Fletcher">{{cite journal|vauthors=Fletcher, S, Grotegut, CA, James, AH |title=Lochia patterns among normal women: a systematic review.|journal=Journal of Women's Health |date=December 2012 |volume=21 |issue=12 |pages=1290–4 |doi=10.1089/jwh.2012.3668 |pmid=23101487}}</ref>

=== Vaginal microbiota ===
{{Main|Vaginal flora}}
{{further|List of microbiota species of the lower reproductive tract of women}}[[File:Lactobacilli (Gram stain).jpg|thumb|Gram stain of lactobacilli and squamous epithelial cells in vaginal swab]]
The [[vaginal flora]] is a complex [[ecosystem]] that changes throughout life, from birth to menopause. The vaginal microbiota resides in and on the outermost layer of the vaginal epithelium.<ref name="Anderson" /> This microbiome consists of species and genera, which typically do not cause symptoms or infections in women with normal immunity. The vaginal microbiome is dominated by ''[[Lactobacillus]]'' species.<ref name="PetrovaLievens2015">{{cite journal |vauthors=Petrova MI, Lievens E, Malik S, Imholz N, Lebeer S |title=Lactobacillus species as biomarkers and agents that can promote various aspects of vaginal health|journal=Frontiers in Physiology|volume=6|pages=81|year=2015|issn=1664-042X|doi=10.3389/fphys.2015.00081|pmid=25859220|pmc=4373506|doi-access=free}}</ref> These species [[Metabolism|metabolize]] glycogen, breaking it down into sugar. ''Lactobacilli'' metabolize the sugar into glucose and lactic acid.<ref name = "King"/> Under the influence of hormones, such as estrogen, progesterone and [[follicle-stimulating hormone]] (FSH), the vaginal ecosystem undergoes cyclic or periodic changes.<ref name="King">{{cite book|vauthors=King TL, Brucker MC|title=Pharmacology for Women's Health|publisher=[[Jones & Bartlett Publishers]]|isbn=978-1-4496-1073-9|year=2010|pages=951–953|url=https://books.google.com/books?id=o_rHHCsIpckC&pg=PA951|access-date=October 27, 2015|archive-date=May 2, 2016|archive-url=https://web.archive.org/web/20160502023957/https://books.google.com/books?id=o_rHHCsIpckC&pg=PA951|url-status=live}}</ref>