Editing Sexual intercourse (section)

===Risks{{anchor|General risks}}===
[[Sexually transmitted infection]]s (STIs) are [[bacteria]], [[virus]]es or [[parasites]] that are [[Transmission (medicine)|spread]] by sexual contact, especially vaginal, anal, or oral intercourse, or [[unprotected sex]].<ref name="Hoeger">{{cite book|vauthors=Hoeger W, HS, FA, HC|title=Principles and Labs for Fitness and Wellness| publisher = [[Cengage Learning]] | year = 2016 | pages = 538–540|isbn = 978-1-337-09997-4| url =https://books.google.com/books?id=wdq5DQAAQBAJ}}</ref><ref name=Women2017>{{Cite web|url=https://www.womenshealth.gov/a-z-topics/sexually-transmitted-infections|title=Sexually transmitted infections|website=womenshealth.gov|language=en|access-date=December 8, 2017|date=February 22, 2017}}{{PD-notice}}</ref> Oral sex is less risky than vaginal or anal intercourse.<ref name="Gulanick">{{cite book|vauthors=Gulanick M, Myers JL |title=Nursing Care Plans - E-Book: Diagnoses, Interventions, and Outcomes| publisher=[[Elsevier Health Sciences]] |year=2016 |page=725|isbn=978-0-323-42810-1| url=https://books.google.com/books?id=NK2ADQAAQBAJ}}</ref> Many times, STIs initially do not cause symptoms, increasing the risk of unknowingly passing the infection on to a sex partner or others.<ref>{{cite book|vauthors=Murray PR, Rosenthal KS, Pfaller MA|title=Medical microbiology|date=2013|publisher=Mosby|location=St. Louis, MO|isbn=978-0-323-08692-9 |page=418|edition=7th|url=https://books.google.com/books?id=RBEVsFmR2yQC&pg=PA418 |url-status=live |archive-url=https://web.archive.org/web/20151201070705/https://books.google.com/books?id=RBEVsFmR2yQC&pg=PA418 |archive-date=December 1, 2015}}</ref><ref>{{cite book|last1=Goering|first1=Richard V.|title=Mims' medical microbiology |date=2012 |publisher=Saunders|location=Edinburgh|isbn=978-0-7234-3601-0 |page=245 |edition=5th |url=https://books.google.com/books?id=pzQayLEQ5mQC&pg=PA245}}</ref>

There are 19 million new cases of sexually transmitted infections every year in the U.S.,<ref>{{cite web|title=STD Trends in the United States: 2010 National Data for Gonorrhea, Chlamydia, and Syphilis |url=https://www.cdc.gov/std/stats10/trends.htm |publisher=[[Centers for Disease Control and Prevention]] |url-status=dead |archive-url=https://web.archive.org/web/20120326175627/https://www.cdc.gov/std/stats10/trends.htm |archive-date=March 26, 2012 |access-date=September 23, 2023}}</ref> and, in 2005, the World Health Organization (WHO) estimated that 448 million people aged 15–49 were infected per year with curable STIs (such as [[syphilis]], [[gonorrhea]] and [[chlamydia]]).<ref name="WHO 2015">{{cite web| title=Sexually transmitted infections (STIs)|publisher=World Health Organization| url =https://www.who.int/mediacentre/factsheets/fs110/en/| access-date = June 20, 2015}}</ref> Some STIs can cause a [[genital ulcer]]; even if they do not, they increase the risk of both acquiring and passing on HIV up to ten-fold.<ref name="WHO 2015"/> [[Hepatitis B]] can also be transmitted through sexual contact.<ref>[https://www.cdc.gov/hepatitis/HBV/HBVfaq.htm#treatment CDC Hepatitis B Information for Health Professionals] Accessed May 27, 2010</ref> Globally, there are about 257 million chronic carriers of hepatitis B.<ref>{{cite web|title=Hepatitis B|url=https://www.who.int/news-room/fact-sheets/detail/hepatitis-b |publisher=[[World Health Organization]] |date=July 18, 2018}}</ref> HIV is one of the world's leading infectious killers; in 2010, approximately 30 million people were estimated to have died because of it since the beginning of the epidemic. Of the 2.7 million new [[Epidemiology of HIV/AIDS|HIV infections]] estimated to occur worldwide in 2010, 1.9 million (70%) were in [[HIV/AIDS in Africa|Africa]]. The World Health Organization also stated that the "estimated 1.2 million Africans who died of HIV-related illnesses in 2010 comprised 69% of the global total of 1.8 million deaths attributable to the epidemic."<ref name=WHO-HIV>{{cite web|title=HIV/AIDS|publisher=[[World Health Organization]] |url=https://www.who.int/gho/hiv/en/index.html|access-date=September 15, 2012}}</ref> It is [[Diagnosis of HIV/AIDS|diagnosed by blood tests]], and while no cure has been found, it can be controlled by management [[Management of HIV/AIDS|through antiretroviral drugs for the disease]], and patients can enjoy healthy and productive lives.<ref name=WHO-2012>{{cite web|title=HIV/AIDS|url=https://www.who.int/mediacentre/factsheets/fs360/en/index.html|work=Fact sheet N° 360|publisher=[[World Health Organization]]|access-date=September 8, 2012|date=July 2012}}</ref>

In cases where infection is suspected, early medical intervention is highly beneficial in all cases. The CDC stated "the risk of HIV transmission from an infected partner through oral sex is much less than the risk of HIV transmission from anal or vaginal sex," but that "measuring the exact risk of HIV transmission as a result of oral sex is very difficult" and that this is "because most sexually active individuals practice oral sex in addition to other forms of sex, such as vaginal or anal sex, when transmission occurs, it is difficult to determine whether it occurred as a result of oral sex or other more risky sexual activities". They added that "several co-factors may increase the risk of HIV transmission through oral sex"; this includes ulcers, [[Bleeding on probing|bleeding gums]], genital sores, and the presence of other STIs.<ref name="CDC, oral sex"/>

In 2005, the World Health Organization estimated that 123 million women become pregnant worldwide each year, and around 87 million of those pregnancies or 70.7% are unintentional. Approximately 46 million pregnancies per year reportedly end in induced [[abortion]].<ref>{{cite web|title=Not Every Pregnancy is Welcome|url=https://www.who.int/whr/2005/chapter3/en/index3.html|archive-url=https://web.archive.org/web/20050414233054/http://www.who.int/whr/2005/chapter3/en/index3.html|url-status=dead|archive-date=April 14, 2005|work=The world health report 2005&nbsp;– make every mother and child count|publisher=[[World Health Organization]]|access-date=December 6, 2011}}</ref> Approximately 6 million U.S. women become pregnant per year. Out of known pregnancies, two-thirds result in live births and roughly 25% in abortions; the remainder end in miscarriage. However, many more women become pregnant and miscarry without even realizing it, instead mistaking the miscarriage for an unusually heavy [[menstruation]].<ref name="Guttmacher 0">{{cite web|title=Get "In the Know": 20 Questions About Pregnancy, Contraception and Abortion |publisher=[[Guttmacher Institute]] |year=2005 |access-date=March 4, 2011 |url=http://www.guttmacher.org/in-the-know/index.html |url-status=deviated |archive-url=https://web.archive.org/web/20091223093547/http://www.guttmacher.org/in-the-know/index.html |archive-date=December 23, 2009 }}</ref> The U.S. [[teenage pregnancy]] rate fell by 27 percent between 1990 and 2000, from 116.3 pregnancies per 1,000 girls aged 15–19 to 84.5. This data includes live births, abortions, and fetal losses. Almost 1 million American teenage women, 10% of all women aged 15–19 and 19% of those who report having had intercourse, become pregnant each year.<ref name="Ventura">{{cite web|author=Ventura, SJ|author2=Abma, JC|author3=Mosher, WD|author4=Henshaw, S.|name-list-style=amp|title=Estimated pregnancy rates for the United States, 1990–2000: An Update. National Vital Statistics Reports, 52 (23)|publisher=[[Centers for Disease Control and Prevention]]|date=November 16, 2007|access-date=March 4, 2011|url=https://www.cdc.gov/nchs/data/nvsr/nvsr52/nvsr52_23.pdf}}</ref>

Sexual activity can increase the expression of a [[gene transcription]] factor called [[ΔFosB]] (delta FosB) in the [[nucleus accumbens|brain's reward center]];<ref name="ΔFosB reward">{{cite journal |vauthors=Blum K, Werner T, Carnes S, Carnes P, Bowirrat A, Giordano J, Oscar-Berman M, Gold M | title = Sex, drugs, and rock 'n' roll: hypothesizing common mesolimbic activation as a function of reward gene polymorphisms | journal = Journal of Psychoactive Drugs | volume = 44 | issue = 1 | pages = 38–55 | year = 2012 | pmid = 22641964 | pmc = 4040958 | doi = 10.1080/02791072.2012.662112}}</ref><ref name="Natural and drug addictions">{{cite journal | author = Olsen CM | title = Natural rewards, neuroplasticity, and non-drug addictions | journal = Neuropharmacology | volume = 61 | issue = 7 | pages = 1109–1122 |date=December 2011 | pmid = 21459101 | pmc = 3139704 | doi = 10.1016/j.neuropharm.2011.03.010 }}</ref><ref name="Amph and sex addiction"><!--Supplemental primary source-->{{cite journal |vauthors=Pitchers KK, Vialou V, [[Eric J. Nestler|Nestler EJ]], Laviolette SR, Lehman MN, Coolen LM | title = Natural and drug rewards act on common neural plasticity mechanisms with ΔFosB as a key mediator | journal = J. Neurosci. | volume = 33 | issue = 8 | pages = 3434–42 |date=February 2013 | pmid = 23426671 | pmc = 3865508 | doi = 10.1523/JNEUROSCI.4881-12.2013 }}</ref> consequently excessively frequent engagement in sexual activity on a regular (daily) basis can lead to the overexpression of ΔFosB, inducing an addiction to sexual activity.<ref name="ΔFosB reward" /><ref name="Natural and drug addictions" /><ref name="Amph and sex addiction" /> [[Sexual addiction]] or [[hypersexuality]] is often considered an impulse control disorder or a behavioral addiction. It has been linked to atypical levels of dopamine, a neurotransmitter. This behavior is characterized by a fixation on sexual intercourse and disinhibition. It was proposed that this 'addictive behavior' be classified in [[DSM-5]] as an impulsive–compulsive behavioral disorder. Addiction to sexual intercourse is thought to be genetically linked. Those having an addiction to sexual intercourse have a higher response to visual sexual cues in the brain. Those seeking [[Psychiatric treatment|treatment]] will typically see a physician for pharmacological management and therapy.<ref name="Probstvan Eimeren2013">{{cite journal|last1=Probst |first1=Catharina C.|last2=van Eimeren|first2=Thilo|title=The Functional Anatomy of Impulse Control Disorders|journal=Current Neurology and Neuroscience Reports|volume=13|issue=10|pages=386|year=2013 |issn=1528-4042|doi=10.1007/s11910-013-0386-8|pmid=23963609|pmc=3779310}}</ref> One form of hypersexuality is [[Kleine–Levin syndrome]]. It is manifested by [[hypersomnia]] and hypersexuality and remains relatively rare.<ref name="GuilleminaultMiglis2014">{{cite journal|last1=Guilleminault|first1=Christian|last2=Miglis|first2=Mitchell|author1-link=Christian Guilleminault|title=Kleine-Levin syndrome: a review|journal=Nature and Science of Sleep|volume=6|pages=19–26|year=2014|issn=1179-1608|doi=10.2147/NSS.S44750|pmid=24470783|pmc=3901778 |doi-access=free }}</ref>

[[Death during consensual sex|Sexual activity can directly cause death]], particularly due to [[coronary circulation]] complications, which is sometimes called ''coital death,'' ''coital sudden death'' or ''coital coronary.''<ref name="Kahn, Fawcett"/><ref name="Kipshidze">{{Cite book|author= Nicolas Kipshidze|author2= Jawad Fareed|author3= Patrick W. Serruys|author4= Jeff Moses | title = Textbook of Interventional Cardiovascular Pharmacology| year = 2007 | publisher = [[CRC Press]] |page=505 | isbn = 978-0-203-46304-8| url=https://books.google.com/books?id=13g_niZy0usC&pg=PA505| access-date=October 21, 2015}}</ref><ref name="Dahabreh">{{cite journal|last=Dahabreh|first=Issa J. |title=Association of Episodic Physical and Sexual Activity With Triggering of Acute Cardiac Events. Systematic Review and Meta-analysis |journal=JAMA: The Journal of the American Medical Association|date=March 23, 2011|volume=305 |issue=12|pages=1225–33|doi=10.1001/jama.2011.336|pmid=21427375|pmc=5479331|quote=Acute cardiac events were significantly associated with episodic physical and sexual activity; this association was attenuated among persons with high levels of habitual physical activity.}}</ref> However, coital deaths are significantly rare.<ref name="Kipshidze"/> People, especially those who get little or no physical exercise, have a slightly increased risk of triggering a [[heart attack]] or [[sudden cardiac death]] when they engage in sexual intercourse or any vigorous physical exercise that is engaged in on a sporadic basis.<ref name="Dahabreh"/> Regular exercise reduces, but does not eliminate, the increased risk.<ref name="Dahabreh"/>