ผลต่างระหว่างรุ่นของ "ผู้ใช้:Pilarbini/กระบะทราย/กรุ 15"

แปะ
(Pilarbini ย้ายหน้า ผู้ใช้:Pilarbini/กระบะทราย/กรุ 15 ไปยัง ดอนนา สตริกแลนด์: สร้างหน้า)
ป้ายระบุ: เปลี่ยนทางใหม่
 
(แปะ)
ป้ายระบุ: การแก้ไขแบบเห็นภาพ ผู้ใช้แก้หน้าเปลี่ยนทาง ลบหน้าเปลี่ยนทาง
{{Infobox Birth control
#เปลี่ยนทาง [[ดอนนา สตริกแลนด์]]
|name = Hormonal Contraception
|image =
|width =
|caption =
|bc_type = Hormonal
|date_first_use = 1960
|rate_type = Pregnancy
|perfect_failure% = Varies by method: 0.05-2
|typical_failure% = Varies by method: 0.05-9
|duration_effect = Various
|reversibility = Upon discontinuation
|user_reminders = Must follow usage schedule
|clinic_interval = Every 3-12 months, depending on method
|STD_protection_YesNo = No
|periods = Withdrawal bleeds are frequently lighter than menstrual periods, and some methods can suppress bleeding altogether
|benefits =
|weight_gain_loss = No proven effect
|risks =
|medical_notes =
}}
 
'''Hormonal contraception''' refers to [[birth control]] methods that act on the [[endocrine system]]. Almost all methods are composed of [[steroid hormones]], although in [[India]] one [[selective estrogen receptor modulator]] is marketed as a contraceptive. The original hormonal method—the [[combined oral contraceptive pill]]—was first marketed as a contraceptive in 1960.<ref>{{cite book |author1=Susan Scott Ricci |author2=Terri Kyle |year=2009 |chapter=Common Reproductive Issues|title=Contraception |publisher=Lippincott Williams & Wilkins| page=119}}</ref> In the ensuing decades many other delivery methods have been developed, although the oral and injectable methods are by far the most popular. Altogether, 18% of the world's contraceptive users rely on hormonal methods.<ref>{{cite journal |author=Jones, Rachel K. |year=2011 |title= Beyond Birth Control: The Overlooked Benefits Of Oral Contraceptive Pills|journal=Guttmacher Institute |volume=November|url=http://www.guttmacher.org/pubs/Beyond-Birth-Control.pdf}}</ref> Hormonal contraception is highly effective: when taken on the prescribed schedule, users of steroid hormone methods experience pregnancy rates of less than 1% per year. Perfect-use pregnancy rates for most hormonal contraceptives are usually around the 0.3% rate or less.<ref name="npsnews">{{cite web |url=http://www.nps.org.au/health_professionals/publications/nps_news/current/hormonal_contraception_tailoring_for_the_individual |title=NPS News 54: Hormonal contraceptives - tailoring for the individual |author=National Prescribing Service |date=11 December 2009 |accessdate=19 March 2009}}</ref> Currently available methods can only be used by women; the development of a [[male hormonal contraceptive]] is an active research area.
 
There are two main types of hormonal contraceptive formulations: ''combined methods'' which contain both an [[estrogen (medication)|estrogen]] and a [[progestin]], and ''progestogen-only methods'' which contain only [[progesterone]] or one of its synthetic analogues (progestins). Combined methods work by suppressing [[ovulation]] and thickening [[cervical mucus]]; while progestogen-only methods reduce the frequency of ovulation, most of them rely more heavily on changes in cervical mucus. The incidence of certain side effects is different for the different formulations: for example, [[breakthrough bleeding]] is much more common with progestogen-only methods. Certain serious complications occasionally caused by estrogen-containing contraceptives are not believed to be caused by progestogen-only formulations: [[deep vein thrombosis]] is one example of this.
 
==Medical uses==
Hormonal contraception is primarily used for the prevention of [[pregnancy]], but is also prescribed for the treatment of [[polycystic ovary syndrome]], menstrual disorders such as [[dysmenorrhea]] and [[menorrhagia]], and [[hirsutism]].<ref>{{cite web|title=Hormonal Contraceptives Offer Benefits Beyond Pregnancy Prevention|url=http://www.acog.org/About_ACOG/News_Room/News_Releases/2009/Hormonal_Contraceptives_Offer_Benefits_Beyond_Pregnancy_Prevention|work=The American College of Obstetricians and Gynecologists|accessdate=5 May 2013}}</ref>
 
===Polycystic ovary syndrome===
Hormonal treatments, such as hormonal contraceptives, are frequently successful at alleviating symptoms associated with [[polycystic ovary syndrome]]. [[Birth control pills]] are often prescribed to reverse the effects of excessive [[androgen]] levels, and decrease ovarian hormone production.<ref>{{cite web|title=Hirsutism and Polycystic Ovary Syndrome|url=http://www.asrm.org/uploadedFiles/ASRM_Content/Resources/Patient_Resources/Fact_Sheets_and_Info_Booklets/hirsutismPCOS.pdf|work=American Society for Reproductive Medicine|accessdate=5 May 2013}}</ref>
 
===Dysmenorrhea===
Hormonal birth control methods such as [[birth control pills]], the [[contraceptive patch]], [[vaginal ring]], [[contraceptive implant]], and [[hormonal IUD]] are used to treat cramping and pain associated with primary [[dysmenorrhea]].<ref>{{cite web|title=Noncontraceptive Benefits of Birth Control Pills|url=http://www.reproductivefacts.org/Noncontraceptive_Benefits_of_Birth_Control_Pills_factsheet/|work=Reproductivefacts.org|publisher=The American Society for Reproductive Medicine|accessdate=5 May 2013}}</ref><ref>{{cite web|title=Dysmenorrhea|url=http://www.acog.org/~/media/For%20Patients/faq046.pdf?dmc=1&ts=20130509T0012463128|work=The American College of Obstetricians and Gynecologists|accessdate=5 May 2013}}</ref>
 
===Menorrhagia===
[[Oral contraceptives]] are prescribed in the treatment of [[menorrhagia]] to help regulate menstrual cycles and prevent prolonged menstrual bleeding. The [[hormonal IUD]] ([[Mirena]]) releases [[levonorgestrel]] which thins the uterine lining, preventing excessive bleeding and loss of iron.<ref>{{cite web|title=Menorrhagia (Heavy Menstrual Bleeding)|url=http://www.mayoclinic.com/health/menorrhagia/DS00394/DSECTION=treatments-and-drugs|work=The Mayo Clinic|accessdate=5 May 2013}}</ref>
 
===Hirsutism===
Birth control pills are the most commonly prescribed hormonal treatment for [[hirsutism]], as they prevent [[ovulation]] and decrease [[androgen]] production by the [[ovaries]]. Additionally, [[estrogen (medication)|estrogen]] in the pills stimulates the liver to produce more of a protein that binds to androgens and reduces their activity.<ref>{{cite web|title=Hirsutism and Polycystic Ovary Syndrome (PCOS)|url=http://www.asrm.org/uploadedFiles/ASRM_Content/Resources/Patient_Resources/Fact_Sheets_and_Info_Booklets/hirsutismPCOS.pdf|work=American Society for Reproductive Medicine|accessdate=5 May 2013}}</ref>
 
===Effectiveness===
Modern contraceptives using steroid hormones have ''perfect-use'' or ''method'' failure rates of less than 1% per year. The lowest failure rates are seen with the implants Jadelle and Implanon, at 0.05% per year.<ref>{{cite journal |vauthors=Sivin I, Campodonico I, Kiriwat O, Holma P, Diaz S, Wan L, Biswas A, Viegas O, el din Abdalla K, Anant MP, Pavez M, Stern J | title = The performance of levonorgestrel rod and Norplant contraceptive implants: a 5 year randomized study | journal = Hum. Reprod. | volume = 13 | issue = 12 | pages = 3371–8 | year = 1998 | pmid = 9886517 | doi = 10.1093/humrep/13.12.3371 }}</ref><ref name="trussell">{{cite book |author=Trussell, James |year=2007 |chapter=Contraceptive Efficacy |editor=Hatcher, Robert A.|title=Contraceptive Technology |edition=19th rev. |pages= |location=New York |publisher=Ardent Media |isbn=0-9664902-0-7 |chapterurl=http://www.contraceptivetechnology.com/table.html|display-editors=etal}}</ref> According to ''Contraceptive Technology'', none of these methods has a failure rate greater than 0.3% per year.<ref name="trussell"/> The SERM ormeloxifene is less effective than the steroid hormone methods; studies have found a perfect-use failure rate near 2% per year.<!--
--><ref name="Puri 1988">{{cite book |vauthors=Puri V, etal |year=1988 |chapter=Results of multicentric trial of Centchroman |editor1=Dhwan B. N. |editor2=et al. |title=Pharmacology for Health in Asia : Proceedings of Asian Congress of Pharmacology, 15–19 January 1985, New Delhi, India |location=Ahmedabad |publisher=Allied Publishers}}</ref><!--
--><ref name="Nityanand 1990">{{cite book |vauthors=Nityanand S, etal |year=1990 |chapter=Clinical evaluation of Centchroman: a new oral contraceptive |editor=Puri, Chander P. |editor2=Van Look, Paul F. A. |title=Hormone Antagonists for Fertility Regulation |location=Bombay |publisher=Indian Society for the Study of Reproduction and Fertility}}</ref>
 
[[Long acting reversible contraceptive|Long-acting methods]] such as the implant and the IUS are user-independent methods.<ref>{{cite journal |last=O'Connor |first=M.L. |title=Contraceptive Use Elevates The Odds of Barrier Method Use for Disease Prevention |journal=Family Planning Perspectives |volume=33 |issue=2 |publisher=Guttmacher Institute |date=March–April 2001 |url=http://www.guttmacher.org/pubs/journals/3309301b.html |accessdate=2009-08-30 |doi=10.2307/2673760 |pages=93}}</ref> For user-independent methods, the ''typical'' or ''actual-use'' failure rates are the same as the method failure rates.<ref name="trussell"/> Methods that require regular action by the user—such as taking a pill every day—have typical failure rates higher than perfect-use failure rates. ''Contraceptive Technology'' reports a typical failure rate of 3% per year for the injection Depo-Provera, and 8% per year for most other user-dependent hormonal methods.<ref name="trussell"/> While no large studies have been done, it is hoped that newer methods which require less frequent action (such as the patch) will result in higher user compliance and therefore lower typical failure rates.<ref>{{cite web |last=Paladine |first=Heather |title=What’s New In Contraception |work=The Female Patient |year=2003 |url=http://www.femalepatient.com/html/arc/sel/feb03/028_02_013.asp |accessdate=2009-08-30}}</ref>
 
===Combined vs. progestogen-only===
While unpredictable [[breakthrough bleeding]] is a possible side effect for all hormonal contraceptives, it is more common with progestogen-only formulations.<ref>'''POP''':{{cite journal | author = Kovacs G | title = Progestogen-only pills and bleeding disturbances | journal = Human Reproduction | volume = 11 | issue = Supplement 2 | pages = 20–3 | date = October 1996 | pmid = 8982741 | doi = 10.1093/humrep/11.suppl_2.20 }}<br/>
'''IUS''':{{cite journal |author=McCarthy L |year=2006 |title=Levonorgestrel-Releasing Intrauterine System (Mirena) for Contraception |journal=Am Fam Physician |volume=73 |issue=10 |pages=1799- | url=http://www.aafp.org/afp/20060515/steps.html | accessdate=2009-09-01}}<br/>
'''Depo-Provera''' and '''Jadelle''':{{cite journal |vauthors=Hubacher D, Lopez L, Steiner MJ, Dorflinger L | title = Menstrual pattern changes from levonorgestrel subdermal implants and DMPA: systematic review and evidence-based comparisons | journal = Contraception | volume = 80 | issue = 2 | pages = 113–8 | date = August 2009 | pmid = 19631785 | doi = 10.1016/j.contraception.2009.02.008 }}<br/>
'''Implanon''':{{cite journal |vauthors=Riney S, O'Shea B, Forde A | title = Etonogestrel implant as a contraceptive choice; patient acceptability and adverse effect profile in a general practice setting | journal = Irish Medical Journal | volume = 102 | issue = 1 | pages = 24–5 | date = January 2009 | pmid = 19284015 }}</ref> <!--
-->Most regimens of COCPs, NuvaRing, and the contraceptive patch incorporate a placebo or break week that causes regular withdrawal bleeding. While women using combined injectable contraceptives may experience [[amenorrhea]] (lack of periods), they typically have predictable bleeding comparable to that of women using COCPs.<ref>{{cite journal |vauthors=Garceau RJ, Wajszczuk CJ, Kaunitz AM | title = Bleeding patterns of women using Lunelle monthly contraceptive injections (medroxyprogesterone acetate and estradiol cypionate injectable suspension) compared with those of women using Ortho-Novum 7/7/7 (norethindrone/ethinyl estradiol triphasic) or other oral contraceptives | journal = Contraception | volume = 62 | issue = 6 | pages = 289–95 | date = December 2000 | pmid = 11239615 | doi = 10.1016/S0010-7824(00)00183-9 }}</ref>
 
Although high-quality studies are lacking,<ref name="truitt">{{cite journal |vauthors=Truitt ST, Fraser AB, Grimes DA, Gallo MF, Schulz KF | title = Hormonal contraception during lactation: systematic review of randomized controlled trials | journal = Contraception | volume = 68 | issue = 4 | pages = 233–8 | date = October 2003 | pmid = 14572885 | doi = 10.1016/S0010-7824(03)00133-1 }}</ref> it is believed that estrogen-containing contraceptives significantly decrease the quantity of milk in breastfeeding women.<!--
--><ref name="kelsey">{{cite journal | author = Kelsey JJ | title = Hormonal contraception and lactation | journal = Journal of Human Lactation | volume = 12 | issue = 4 | pages = 315–8 | date = December 1996 | pmid = 9025449 | doi = 10.1177/089033449601200419 }}</ref> Progestogen-only contraceptives are not believed to have this effect.<ref name="kelsey"/> In addition, while in general the progestogen-only pill is less effective than other hormonal contraceptives, the added [[Lactational amenorrhea method|contraceptive effect of breastfeeding]] makes it highly effective in breastfeeding women.<!--
--><ref>{{cite journal | title = Maximizing the use of the progestin minipill | journal = Contraceptive Technology Update | volume = 20 | issue = 2 | pages = 19–21 | date = February 1999 | pmid = 12294591 }}</ref>
 
While combined contraceptives increase the risk for [[deep vein thrombosis]] (DVT - blood clots), progestogen-only contraceptives are not believed to affect DVT formation.<ref>{{cite web |title=Progestin-only Contraceptives |work=Hall Health Primary Care Center |publisher=University of Wisconsin-Seattle |date=2007-02-11 |url=http://depts.washington.edu/hhpccweb/article-detail.php?ArticleID=105&ClinicID=1 |accessdate=2009-09-01}}</ref>
 
==Side effects==
 
===Cancers===
*There is a mixed effect of combined hormonal contraceptives on the rates of various cancers, with the [[International Agency for Research on Cancer]] (IARC) stating: "It was concluded that, if the reported association was causal, the excess risk for breast cancer associated with typical patterns of current use of combined oral contraceptives was very small."<ref name=IARC99 /><ref name=IARC2007>{{Cite journal | publisher = [[International Agency for Research on Cancer]] | work = IARC Monographs on the Evaluation of Carcinogenic Risks to Humans | volume = 91 | year = 2007 | title = Combined Estrogen-Progestogen Contraceptives | format = [[Portable Document Format|PDF]] | url = http://monographs.iarc.fr/ENG/Monographs/vol91/mono91-6.pdf }}</ref> and also saying that "there is also conclusive evidence that these agents have a protective effect against cancers of the ovary and endometrium":<ref name=IARC99>{{cite book | author=International Agency for Research on Cancer (IARC) | title=Oral Contraceptives, Combined | edition=Vol. 72 | year=1999 | chapter=5. Summary of Data Reported and Evaluation | chapterurl=http://www.inchem.org/documents/iarc/vol72/vol72-1.html | page=49}}</ref>
* The (IARC) notes that "the weight of the evidence suggests a small increase in the relative risk for breast cancer among current and recent users" which following discontinuation then lessens over a period of 10 years to similar rates as women who never used them, as well as "The increase in risk for breast cancer associated with the use of combined oral contraceptives in younger women could be due to more frequent contacts with doctors" <ref name=IARC2007/>
* Small increases are also seen in the rates of [[cervical cancer]] and [[Hepatocellular carcinoma|hepatocellular (liver) tumours]].
* [[Endometrial cancer|Endometrial]]<ref>{{cite journal|title=Endometrial cancer and oral contraceptives: an individual participant meta-analysis of 27 276 women with endometrial cancer from 36 epidemiological studies|journal=Lancet|date=Aug 4, 2015|doi=10.1016/S1470-2045(15)00212-0|volume=16|pages=1061–1070|pmid=26254030}}</ref> and [[ovarian cancer]] risks are approximately halved and persists for at least 10 years after cessation of use; although "sequential oral contraceptives which were removed from the consumer market in the 1970s was associated with an increased risk for endometrial cancer".
* Studies have overall not shown effects on the relative risks for colorectal, malignant melanoma or thyroid cancers.
* Information on progesterone-only pills is less extensive, due to smaller sampling sizes, but they do not appear to significantly increase the risk of breast cancer.<ref name=iarc72>{{cite book |author=IARC Working Group on the Evaluation of Carcinogenic Risks to Humans |title=Hormonal contraception and post-menopausal hormonal therapy; IARC monographs on the evaluation of carcinogenic risks to humans, Volume 72 |year=1999 |publisher=IARC Press |location=Lyon |isbn=92-832-1272-X |pages=339&ndash;397 |chapter=Hormonal contraceptives, progestogens only |chapterurl=http://www.inchem.org/documents/iarc/vol72/vol72-2.html}}</ref>
* Most other forms of hormonal contraception are too new for meaningful data to be available, although risks and benefits are believed to be similar for methods which use the same hormones; e.g., risks for combined-hormone patches are thought to be roughly equivalent to those for combined-hormone pills.<ref>{{cite web| accessdate=2007-07-13| url=http://www.mckinley.uiuc.edu/Handouts/orthoevra_patch.html| title=McKinley Health Center, University of Illinois: OrthoEvra Contraceptive Patch}}</ref>
 
===Cardiovascular disease===
Combined oral contraceptives can increase the risk of certain types of cardiovascular disease in women with a pre-existing condition or already-heightened risk of cardiovascular disease. Smoking (for women over 35), metabolic conditions like diabetes, obesity and family history of heart disease are all risk factors which may be exacerbated by the use of certain hormonal contraceptives.<ref name="npsnews" />
 
===Blood Clots===
Hormonal contraception methods are consistently linked with the risk of developing blood clots. However, the risk does vary depending on the hormone type or birth control method being used.<ref>{{cite web|title=Blood Clots with Hormonal Contraception|url=http://www.hormonesmatter.com/blood-clots-hormonal-contraception/|website=Hormones Matter|date=27 January 2016}}</ref>
 
=== Depression ===
There is a growing body of research evidence investigating the links between hormonal contraception, and potential adverse effects on women’s psychological health.<ref name=":0">{{Cite journal|last=Zettermark|first=Sofia|last2=Vicente|first2=Raquel Perez|last3=Merlo|first3=Juan|date=2018-03-22|title=Hormonal contraception increases the risk of psychotropic drug use in adolescent girls but not in adults: A pharmacoepidemiological study on 800 000 Swedish women|url=http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0194773|journal=PLOS ONE|language=en|volume=13|issue=3|pages=e0194773|doi=10.1371/journal.pone.0194773|issn=1932-6203}}</ref><ref name=":1">{{Cite journal|last=Skovlund|first=Charlotte Wessel|last2=Mørch|first2=Lina Steinrud|last3=Kessing|first3=Lars Vedel|last4=Lidegaard|first4=Øjvind|date=2016-11-01|title=Association of Hormonal Contraception With Depression|journal=JAMA Psychiatry|volume=73|issue=11|pages=1154–1162|doi=10.1001/jamapsychiatry.2016.2387|issn=2168-6238|pmid=27680324}}</ref><ref>{{Cite journal|last=Kulkarni|first=Jayashri|date=July 2007|title=Depression as a side effect of the contraceptive pill|journal=Expert Opinion on Drug Safety|volume=6|issue=4|pages=371–374|doi=10.1517/14740338.6.4.371|issn=1744-764X|pmid=17688380}}</ref> Findings from a large Danish study of one million women (followed up from 2000-2013) were published in 2016, and reported that the use of hormonal contraception was associated with a statistically significant increased risk of subsequent depression, particularly amongst adolescents.<ref name=":1" /> Within this study, women on the progestogen-only pill in particular, were 34% more likely to be subsequently be given a first diagnosis of depression or to take anti-depressants, in comparison to those not on hormonal contraception.<ref name=":1" /> Similarly, in 2018, another large cohort study in Sweden with women aged 12–30 (n=815,662) found an association between hormonal contraception and subsequent use of psychotropic drugs, particularly amongst adolescents (aged 12–19).<ref name=":0" /> These studies highlight the need for further research into the links between hormonal contraception, and adverse effects on women’s psychological health.
 
==Types==
There are two main classes of hormonal contraceptives: ''combined contraceptives'' contain both an estrogen (usually [[ethinylestradiol]]) and a [[progestin]]. ''Progestogen-only contraceptives'' contain only [[progesterone]] or a synthetic analogue (progestin). Also marketed is [[ormeloxifene]]; while not a hormone, ormeloxifene acts on the hormonal system to prevent pregnancy.
 
===Combined===
The most popular form of hormonal contraception, the [[combined oral contraceptive pill]] is known colloquially as ''the pill''. It is taken once a day, most commonly for 21 days followed by a seven-day break, although other regimens are also used. For women not using ongoing hormonal contraception, COCPs may be taken after intercourse as [[emergency contraception]]: this is known as the [[Yuzpe regimen]]. COCPs are available in [[oral contraceptive formulations|a variety of formulations]].
 
The [[contraceptive patch]] is applied to the skin and worn continuously. A series of three patches are worn for one week each, and then the user takes a one-week break. [[NuvaRing]] is worn inside the vagina. A ring is worn for three weeks. After removal, the user takes a one-week break before inserting a new ring. As with COCPs, other regimens may be used with the contraceptive patch or NuvaRing to provide [[extended cycle combined hormonal contraception]].
 
Some [[combined injectable contraceptive]]s can be administered as one injection per month.
 
===Progestogen-only===
The [[progestogen only pill]] (POP) is taken once per day within the same three-hour window. [[Oral contraceptive formulations#Progestogen only pills|Several different formulations]] of POP are marketed. A low-dose formulation is known as ''the minipill''. Unlike COCPs, progestogen-only pills are taken every day with no breaks or placebos. For women not using ongoing hormonal contraception, progestogen-only pills may be taken after intercourse as [[emergency contraception]]. There are a number of [[Emergency contraceptive availability by country|dedicated products]] sold for this purpose.
 
Hormonal intrauterine contraceptives are known as [[intrauterine system]]s (IUS) or Intrauterine Devices (IUD). An IUS/IUD must be inserted by a health professional. The copper IUD does not contain hormones. While a copper-containing IUD may be used as emergency contraception, the IUS has not been studied for this purpose.
 
[[Depo Provera]] is an injection that provides three months of contraceptive protection. Noristerat is another injection; it is given every two months.<ref>{{cite web |last=Stacey |first=Dawn |title=Noristerat Injection |work=About.com |date=2009-07-28 |url=http://contraception.about.com/od/prescriptionoptions/g/Noristerat.htm |accessdate=2009-08-29}}</ref>
 
[[Contraceptive implants]] are inserted under the skin of the upper arm, and contain progesterone only. [[Jadelle]] (Norplant 2) consists of two rods that release a low dose of hormones. It is effective for five years. Nexplanon has replaced the former [[Implanon]] and is also a single rod that releases etonogestrel (similar to the body's natural progesterone). The only difference between Implanon and Nexplanon is Nexplanon is radio opaque and can be detected by x-ray. This is needed for cases of implant migration. It is effective for three years and is usually done in office. It is over 99% effective. It works in 3 ways:
1. Prevents ovulation- usually an egg does not mature
2. thickens cervical mucus so to prevent sperm from reaching the egg
3. If those 2 fail, the last is the progesterone causes the lining of the uterus to be too thin for implantation.
 
===Ormeloxifene===
[[Ormeloxifene]] is a [[selective estrogen receptor modulator]] (SERM). Marketed as Centchroman, Centron, or Saheli, it is pill that is taken once per week. Ormeloxifene is legally available only in [[India]].<ref name="centron"/>
 
==Mechanism of action==
The effect of hormonal agents on the reproductive system is complex. It is believed that combined hormonal contraceptives work primarily by preventing ovulation and thickening cervical mucus. Progestogen-only contraceptives can also prevent ovulation, but rely more significantly on the thickening of cervical mucus. Ormeloxifene does not affect ovulation, and its mechanism of action is not well understood.
 
===Combined===
Combined hormonal contraceptives were developed to prevent [[ovulation]] by suppressing the release of [[gonadotropin]]s. They inhibit [[follicular phase|follicular development]] and prevent ovulation as a primary mechanism of action.<ref name="Nelson 2011">{{cite book|last1=Nelson|first1=Anita L.|last2=Cwiak|first2=Carrie|year=2011|chapter=Combined oral contraceptives (COCs)|editor1-last=Hatcher|editor1-first=Robert A.|editor2-last=Trussell|editor2-first=James|editor3-last=Nelson|editor3-first=Anita L.|editor4-last=Cates|editor4-first=Willard Jr.|editor5-last=Kowal|editor5-first=Deborah|editor6-last=Policar|editor6-first=Michael S. (eds.)|title=Contraceptive technology|edition=20th revised|location=New York|publisher=Ardent Media|pages=249–341|isbn=978-1-59708-004-0|issn=0091-9721|oclc=781956734}} pp. 257–258:<blockquote>Mechanism of action<br/>COCs prevent fertilization and, therefore, qualify as contraceptives. There is no significant evidence that they work after fertilization. The progestins in all COCs provide most of the contraceptive effect by suppressing ovulation and thickening cervical mucus, although the estrogens also make a small contribution to ovulation suppression. Cycle control is enhanced by the estrogen.<br/>Because COCs so effectively suppress ovulation and block ascent of sperm into the upper genital tract, the potential impact on endometrial receptivity to implantation is almost academic. When the two primary mechanisms fail, the fact that pregnancy occurs despite the endometrial changes demonstrates that those endometrial changes do not significantly contribute to the pill's mechanism of action.</blockquote></ref><ref name="Speroff 2011">{{cite book|last1=Speroff|first1=Leon|last2=Darney|first2=Philip D.|year=2011|chapter=Oral contraception|title=A clinical guide for contraception|edition=5th|location=Philadelphia|publisher=Lippincott Williams & Wilkins|pages=19–152|isbn=978-1-60831-610-6}}</ref><ref name="Levin 2011">{{cite book|last1=Levin|first=Ellis R.|last2=Hammes|first2=Stephen R.|year=2011|chapter=Estrogens and progestins|editor1-last=Brunton|editor1-first=Laurence L.|editor2-last=Chabner|editor2-first=Bruce A.|editor3-last=Knollmann|editor3-first=Björn C.|title=Goodman & Gilman's pharmacological basis of therapeutics|edition=12th|location=New York|publisher=McGraw-Hill Medical|pages=1163–1194|isbn=978-0-07-162442-8}}</ref><ref name="Glasier 2010">{{cite book|last=Glasier|first=Anna|year=2010|chapter=Contraception|editor1-last=Jameson|editor1-first=J. Larry|editor2-last=De Groot|editor2-first=Leslie J.|title=Endocrinology|edition=6th|location=Philadelphia|publisher=Saunders Elsevier|pages=2417–2427|isbn=978-1-4160-5583-9}}</ref>
 
Progestogen [[negative feedback]] decreases the pulse frequency of [[gonadotropin-releasing hormone]] (GnRH) release by the [[hypothalamus]], which decreases the release of [[follicle-stimulating hormone]] (FSH) and greatly decreases the release of [[luteinizing hormone]] (LH) by the [[anterior pituitary]]. Decreased levels of FSH inhibit follicular development, preventing an increase in [[estradiol]] levels. Progestogen negative feedback and the lack of estrogen [[positive feedback]] on LH release prevent a [[menstrual cycle|mid-cycle]] LH surge. Inhibition of follicular development and the absence of a LH surge prevent ovulation.<ref name="Nelson 2011"/><ref name="Speroff 2011"/><ref name="Levin 2011"/>
 
Estrogen was originally included in oral contraceptives for better cycle control (to stabilize the endometrium and thereby reduce the incidence of breakthrough bleeding), but was also found to inhibit follicular development and help prevent ovulation. Estrogen negative feedback on the anterior pituitary greatly decreases the release of FSH, which inhibits follicular development and helps prevent ovulation.<ref name="Nelson 2011"/><ref name="Speroff 2011"/><ref name="Levin 2011"/>
 
Another primary mechanism of action of all progestogen-containing contraceptives is inhibition of [[spermatozoon|sperm]] penetration through the [[cervix]] into the upper [[female reproductive system (human)|genital tract]] ([[uterus]] and [[fallopian tube]]s) by decreasing the amount of and increasing the [[viscosity]] of the [[cervical mucus]].<ref name="Nelson 2011"/>
 
The estrogen and progestogen in combined hormonal contraceptives have other effects on the reproductive system, but these have not been shown to contribute to their contraceptive efficacy:<ref name="Nelson 2011"/>
* Slowing tubal motility and ova transport, which may interfere with [[human fertilization|fertilization]].
* [[Endometrium|Endometrial]] atrophy and alteration of [[metalloproteinase]] content, which may impede sperm motility and viability, or theoretically inhibit [[implantation (human embryo)|implantation]].
* Endometrial edema, which may affect implantation.
 
Insufficient evidence exists on whether changes in the endometrium could actually prevent implantation. The primary mechanisms of action are so effective that the possibility of fertilization during combined hormonal contraceptive use is very small. Since pregnancy occurs despite endometrial changes when the primary mechanisms of action fail, endometrial changes are unlikely to play a significant role, if any, in the observed effectiveness of combined hormonal contraceptives.<ref name="Nelson 2011"/>
 
===Progestogen-only===
The mechanism of action of progestogen-only contraceptives depends on the [[progestogen]] activity and dose.<ref name="Glasier 2010"/>
 
Low dose progestogen-only contraceptives include traditional progestogen-only pills, the subdermal implant [[Jadelle]] and the [[intrauterine system]] Mirena. These contraceptives inconsistently inhibit ovulation in ~50% of cycles and rely mainly on their progestogenic effect of thickening the [[cervical mucus]] and thereby reducing sperm viability and penetration.
 
Intermediate dose progestogen-only contraceptives, such as the progestogen-only pill Cerazette (or the subdermal implant [[Implanon]]), allow some follicular development but much more consistently inhibit ovulation in 97–99% of cycles. The same cervical mucus changes occur as with low dose progestogens.
 
High dose progestogen-only contraceptives, such as the injectables [[Depo-Provera]] and Noristerat, completely inhibit follicular development and ovulation. The same cervical mucus changes occur as with very low dose and intermediate dose progestogens.
 
In [[anovulation|anovulatory cycles]] using progestogen-only contraceptives, the endometrium is thin and atrophic. If the endometrium was also thin and atrophic during an ovulatory cycle, this could theoretically interfere with implantation of a blastocyst (embryo).
 
===Ormeloxifene===
Ormeloxifene does not affect ovulation. It has been shown to increase the rate of [[blastocyst]] development and to increase the speed at which the blastocyst is moved from the [[fallopian tube]]s into the uterus. Ormeloxifene also suppresses proliferation and [[decidualization]] of the [[endometrium]] (the transformation of the endometrium in preparation for possible implantation of an embryo).<ref name="centron">{{cite web |title=Centchroman |work=Reproductive Health Online |year=2003 |url=http://www.reproline.jhu.edu/english/1fp/1advances/old/1centch/ceorvw.htm |accessdate=2009-08-29}}</ref> While they are believed to prevent [[Implantation (human embryo)|implantation]] rather than [[Human fertilization|fertilization]], exactly how these effects operate to prevent pregnancy is not understood.
 
==Frequency of use==
Pills—combined and progestogen-only—are the most common form of hormonal contraception. Worldwide, they account for 12% of contraceptive use. 21% of users of reversible contraceptives choose COCPs or POPs. Pills are especially popular in more developed countries, where they account for 25% of contraceptive use.<!--
--><ref name="factsheet">{{cite journal |title=Family Planning Worldwide: 2008 Data Sheet |publisher=Population Reference Bureau |year=2008 |url=http://www.prb.org/pdf08/fpds08.pdf |format=PDF |accessdate=2008-06-27 }} Data from surveys 1997–2007.</ref><!--
Note: percent of contraceptive users using pills calculated by dividing % of women using pills by percent of women using any method of contraception -->
 
Injectable hormonal contraceptives are also used by a significant portion—about 6%—of the world's contraceptive users.<ref name="factsheet"/><ref name="nsfg">{{cite journal | last= Chandra |first=A |author2=Martinez GM |author3=Mosher WD |author4=Abma JC |author5=Jones J. |title=Fertility, Family Planning, and Reproductive Health of U.S. Women: Data From the 2002 National Survey of Family Growth |publisher=National Center for Health Statistics | journal = Vital and Health Statistics | volume = 23 | issue = 25 |year=2005 |url=https://www.cdc.gov/nchs/data/series/sr_23/sr23_025.pdf |format=PDF |accessdate=2007-05-20 }} See Table 60.</ref> Other hormonal contraceptives are less common, accounting for less than 1% of contraceptive use.<ref name="factsheet"/><ref name="nsfg"/>
 
==History==
In 1921, [[Ludwig Haberlandt]] demonstrated a temporary hormonal contraception in a female rabbit by transplanting ovaries from a second, pregnant, animal.<ref>{{cite journal | author = Müller-Jahncke WD | title = Ludwig Haberlandt (1885-1932) and the development of hormonal contraception | language = German| journal = Z Gesamte Inn Med | volume = 43 | issue = 15 | pages = 420–2 | date = Aug 1988 | pmid = 3051743 | url = | laysummary = | oclc = | id = | bibcode = | accessdate = | location = GERMANY, EAST | laydate = | format = | quote = | publisher = | issn = 0044-2542 | laysource = }}</ref> By the 1930s, scientists had isolated and determined the structure of the [[steroid hormones]] and found that high doses of [[androgens]], [[estrogen]]s, or [[progesterone]] inhibited [[ovulation]].<!--
--><ref name="goldzieher 1982">{{cite journal | author = Goldzieher JW | title = Estrogens in oral contraceptives: historical perspective | journal = Johns Hopkins Med J | volume = 150 | issue = 5 | pages = 165–9 | year = 1982 | pmid = 7043034 }}</ref><!--
--><ref name="perone 1974">{{cite journal | author = Perone N | title = The history of steroidal contraceptive development: the progestins | journal = Perspect Biol Med | volume = 36 | issue = 3 | pages = 347–62 | year = 1993 | pmid = 8506121 | doi=10.1353/pbm.1993.0054}}</ref> A number of economic, technological, and social obstacles had to be overcome before the development of the first hormonal contraceptive, the [[combined oral contraceptive pill]] (COCP). In 1957 [[Enovid]], the first COCP, was approved in the [[United States]] for the treatment of menstrual disorders. In 1960, the U.S. [[Food and Drug Administration]] approved an application that allowed Enovid to be marketed as a contraceptive.<!--
--><ref name="junod">{{cite journal |vauthors=Junod SW, Marks L | title = Women's trials: the approval of the first oral contraceptive pill in the United States and Great Britain | journal = J Hist Med Allied Sci | volume = 57 | issue = 2 | pages = 117–60 | year = 2002 | pmid = 11995593 | doi = 10.1093/jhmas/57.2.117 | url = http://jhmas.oxfordjournals.org/cgi/reprint/57/2/117.pdf | format = PDF }}</ref>
 
The first progestogen-only contraceptive was introduced in 1969: [[Depo-Provera]], a high-dose progestin injection.<ref>{{cite news |last=Leary |first=Warren E. |date=1992-10-30 |title=U.S. Approves Injectable Drug As Birth Control |journal=[[The New York Times]] |url=https://query.nytimes.com/gst/fullpage.html?sec=health&res=9E0CE1DD123BF933A05753C1A964958260 |pmid=11646958 | page=A.1}}</ref> Over the next decade and a half, other types of progestogen-only contraceptive were developed: a low-dose [[progestogen only pill]] (1973);<ref>{{cite news |last=McFadden |first=Suzanne |title=Golden anniversary of a revolution |work=The New Zealand Herald |date=2009-06-15 |url=http://www.nzherald.co.nz/healthy-living/news/article.cfm?c_id=1501238&objectid=10578586&pnum=3 |accessdate=2009-08-29}}</ref> Progestasert, the first [[Intrauterine system|hormonal intrauterine device]] (1976);<ref>{{cite journal |title=IUDs—An Update |journal=Population Information Program, the Johns Hopkins School of Public Health |date=December 1995 |volume=XXIII |issue=5 |url=http://www.infoforhealth.org/pr/b6edsum.shtml |chapterurl=http://www.infoforhealth.org/pr/b6/b6chap2_1.shtml#top |chapter=Chapter 2: Types of IUDs}}</ref> and [[Norplant]], the first contraceptive implant (1983).<ref>{{cite web |last=Chin |first=Mona |title=The Chronological Important Events in the Development of Norplant |work=Norplant |year=1992 |url=http://www.csua.berkeley.edu/~monac/norplant.html |accessdate=2009-08-29}}, possibly taken from
:{{cite journal |last=Dorflinger |first=LJ |title=Explanation of assumptions made for Norplant projections |journal=Unpublished |date=1991-08-02 |url=http://db.jhuccp.org/ics-wpd/exec/icswppro.dll?BU=http://db.jhuccp.org/ics-wpd/exec/icswppro.dll&QF0=DocNo&QI0=106723&TN=Popline&AC=QBE_QUERY&RF=LongRecordDisplay |accessdate=2009-08-29}}</ref>
 
Combined contraceptives have also been made available in a variety of forms. In the 1960s a few [[combined injectable contraceptive]]s were introduced, notably Injectable Number 1 in [[People's Republic of China|China]] and Deladroxate in [[Latin America]].<ref>{{cite journal |title=Research and regulatory approval (of injectable contraceptives) |journal=Population Reports |publisher=AccessMyLibrary |date=1995-08-01 |url=http://www.accessmylibrary.com/article-1G1-17773564/research-and-regulatory-approval.html |accessdate=2009-08-29}}</ref> A third combined injection, Cyclo-Provera, was reformulated in the 1980s by lowering the dose and renamed Cyclofem (also called Lunelle). Cyclofem and Mesigyna, another formulation developed in the 1980s, were approved by the [[World Health Organization]] in 1993.<ref>{{cite news |title=World Health Agency Endorsing 2 New Injectable Contraceptives |work=The New York Times |page=Section 1, p.20 |date=1993-06-06 |url=https://www.nytimes.com/1993/06/06/world/world-health-agency-endorsing-2-new-injectable-contraceptives.html |accessdate=2009-08-29}}</ref> [[NuvaRing]], a contraceptive vaginal ring, was first marketed in 2002.<ref>{{cite web |author=Organon |date=July 16, 2002 |title=NuvaRing world's first vaginal birth control ring, first launch now in the US |url=http://www.nuvaring.com/Authfiles/Images/309_76087.pdf |format=PDF|accessdate=2009-08-29 |authorlink=Organon International |archiveurl=https://web.archive.org/web/20051027235801/http://www.nuvaring.com/Authfiles/Images/309_76087.pdf |archivedate=2005-10-27}}</ref> 2002 also saw the launch of Ortho Evra, the first [[contraceptive patch]].<ref>{{cite news |author=Associated Press |title=FDA Approves Contraceptive Patch |work=Wired.com |date=2001-11-11 |url=https://www.wired.com/medtech/health/news/2001/11/48555 |accessdate=2009-08-29}}</ref>
 
In 1991, [[ormeloxifene]] was introduced as a contraceptive in [[India]].<ref name="pmid11410933">{{cite journal | author = Singh MM | title = Centchroman, a selective estrogen receptor modulator, as a contraceptive and for the management of hormone-related clinical disorders | journal = Medical Research Reviews | volume = 21 | issue = 4 | pages = 302–47 | date = July 2001 | pmid = 11410933 | doi = 10.1002/med.1011 }}</ref> While it acts on the estrogen hormonal system, it is atypical in that it is a [[selective estrogen receptor modulator]] rather than an estrogen, and has the capacity for both estrogenic and [[antiestrogen]]ic effects.<ref name="pmid11410933" />
 
==See also==
* [[Reproductive Health Supplies Coalition]]
* [[Male contraceptive#Medications|Male hormonal contraception]]
* [[Progestogen-only injectable contraceptive]]
* [[Estradiol-containing oral contraceptive]]
* [[List of progestogens available in the United States]]
* [[List of estrogens available in the United States]]
 
==References==
{{Reflist}}
 
 
{{Birth control methods}}
{{Hormonal contraceptives}}
 
{{DEFAULTSORT:Hormonal Contraception}}
 
[[Category:Hepatotoxins]]
[[Category:Hormonal contraception| ]]
[[Category:Human female endocrine system]]
[[Category:Sex and drugs]]
4,262

การแก้ไข