Editing Emergency contraception (section)

==Emergency contraceptive pills==
Emergency contraceptive pills (ECPs) are sometimes referred to as emergency hormonal contraception (EHC). They are taken after [[unprotected sex|unprotected sexual intercourse]] or the breakage of a [[condom]].<ref name="fr 1997">{{cite journal |author=Food and Drug Administration (FDA) |date=February 25, 1997 |title=Certain combined oral contraceptives for use as postcoital emergency contraception |journal=Federal Register |volume=62 |issue=37 |pages=8610–8612 |url=http://www.gpo.gov/fdsys/pkg/FR-1997-02-25/pdf/97-4663.pdf}}</ref>

===Types===
A variety of emergency contraceptive pills are available, including combined estrogen and progestin pills; progestin-only ([[levonorgestrel]], LNG) pills; and [[antiprogestogen|antiprogestin]] ([[ulipristal acetate]] or [[mifepristone]]) pills.<ref name="Trussell 2014">{{cite web| vauthors = Trussell J, Raymond EG, Cleland K |date=February 2014|title=Emergency contraception: a last chance to prevent unintended pregnancy|location=Princeton|publisher=Office of Population Research at Princeton University, Association of Reproductive Health Professionals|url=http://ec.princeton.edu/questions/ec-review.pdf|access-date=March 25, 2014|archive-date=September 23, 2010|archive-url=https://web.archive.org/web/20100923040101/http://ec.princeton.edu/questions/ec-review.pdf|url-status=dead}}</ref> Progestin-only and anti-progestin pills are available as specifically packaged pills for use as emergency contraceptive pills.<ref name="Trussell 2014"/><ref name="Gemzell-Danielsson 2013">{{cite journal | vauthors = Gemzell-Danielsson K, Rabe T, Cheng L | title = Emergency contraception | journal = Gynecological Endocrinology | volume = 29 | issue = Supplement 1 | pages = 1–14 | date = March 2013 | pmid = 23437846 | doi = 10.3109/09513590.2013.774591 | s2cid = 27722686 }}</ref> Emergency contraceptive pills originally contained higher [[Dose (biochemistry)|doses]] of the same [[hormone]]s ([[estrogen (medication)|estrogen]]s, [[progestin]]s, or both) found in regular [[combined oral contraceptive pill]]s. Combined estrogen and progestin pills are no longer recommended as dedicated emergency contraceptive pills (because this regimen is less effective and caused more nausea), but certain regular combined oral contraceptive pills (taken 2–5 at a time in what was called "the [[Yuzpe regimen]]") have also been shown to be effective as emergency contraceptive pills.<ref name="Trussell 2014"/>

Progestin-only emergency contraceptive pills contain levonorgestrel, either as a single tablet (or historically, as a split dose of two tablets taken 12&nbsp;hours apart), effective up to 72&nbsp;hours after intercourse.<ref name="Trussell 2014"/> Progestin-only ECPs are sold under many different brand names.<ref name="Trussell 2013">{{cite web|last1=Trussell|first1=James|last2=Cleland|first2=Kelly|date=February 13, 2013|title=Dedicated emergency contraceptive pills worldwide|location=Princeton|publisher=Office of Population Research at Princeton University, Association of Reproductive Health Professionals|url=http://ec.princeton.edu/pills/Dedicated_ECPs.pdf|access-date=March 25, 2014|archive-date=March 4, 2016|archive-url=https://web.archive.org/web/20160304190311/http://ec.princeton.edu/pills/Dedicated_ECPs.pdf|url-status=dead}}</ref><ref name="ICEC 2014">{{cite web|author=ICEC|year=2014|title=EC pill types and countries of availability, by brand|location=New York|publisher=International Consortium for Emergency Contraception (ICEC)|url=http://www.cecinfo.org/country-by-country-information/status-availability-database/ec-pill-types-and-countries-of-availability-by-brand/|access-date=March 25, 2014|archive-date=April 5, 2016|archive-url=https://web.archive.org/web/20160405095026/http://www.cecinfo.org/country-by-country-information/status-availability-database/ec-pill-types-and-countries-of-availability-by-brand/|url-status=usurped}}</ref><ref name="ECEC 2014">{{cite web|author=ECEC|year=2014|title=Emergency contraception availability in Europe|location=New York|publisher=European Consortium for Emergency Contraception (ECEC)|url=http://www.ec-ec.org/emergency-contraception-in-europe/emergency-contraception-availability-in-europe/|access-date=March 25, 2014}}</ref> Progestin-only ECPs are available [[over-the-counter drug|over-the-counter]] (OTC) in many countries (e.g. Australia, Bangladesh, Bulgaria, Canada, Cyprus, Czech Republic, Denmark, Estonia, India, Malta, Netherlands, Norway, Portugal, Romania, Slovakia, South Africa, Sweden, United States), from a pharmacist without a prescription, and available with a prescription in some other countries.<ref name="Trussell 2013"/><ref name="ICEC 2014"/><ref name="ECEC 2014"/>

The antiprogestin ulipristal acetate is available as a micronized emergency contraceptive tablet, effective up to 120&nbsp;hours after intercourse.<ref name="Trussell 2014"/><ref name="Gemzell-Danielsson 2013"/> Ulipristal acetate ECPs developed by [[HRA Pharma]] are available over the counter in Europe<ref>{{cite journal | vauthors = Italia S, Brand H | title = Status of Emergency Contraceptives in Europe One Year after the European Medicines Agency's Recommendation to Switch Ulipristal Acetate to Non-Prescription Status | journal = Public Health Genomics | volume = 19 | issue = 4 | pages = 203–210 |year = 2016 | pmid = 27022731 | doi = 10.1159/000444686 | doi-access = free }}</ref> and by prescription in over 50 countries under the brand names ellaOne, ella (marketed by [[Actavis|Watson Pharmaceuticals]] in the United States), Duprisal 30, Ulipristal 30, and UPRIS.<ref name="Trussell 2013"/><ref name="ICEC 2014"/><ref name="ECEC 2014"/><ref name="ellaOne">{{cite web|author=HRA Pharma|author-link=HRA Pharma|date=March 2013|title=Countries where ellaOne was launched|location=Paris|publisher=[[HRA Pharma]]|url=http://www.ellaone.com/#countries|access-date=March 25, 2014|archive-url=https://web.archive.org/web/20130728203014/http://www.ellaone.com/#countries|archive-date=July 28, 2013|url-status=dead}}</ref>

The antiprogestin [[mifepristone]] (also known as RU-486) is available in five countries as a low-dose or mid-dose emergency contraceptive tablet, effective up to 120 hours after intercourse.<ref name="Trussell 2014"/><ref name="Gemzell-Danielsson 2013"/> Low-dose mifepristone ECPs are available by prescription in Armenia, Russia, Ukraine, and Vietnam and from a pharmacist without a prescription in China.<ref name="Trussell 2013"/><ref name="ICEC 2014"/> Mid-dose mifepristone ECPs are available by prescription in China and Vietnam.<ref name="Trussell 2013"/><ref name="ICEC 2014"/>

Combined estrogen ([[ethinylestradiol]]) and progestin (levonorgestrel or [[norgestrel]]) pills used to be available as dedicated emergency contraceptive pills under several brand names: ''Schering PC4'', ''Tetragynon'', ''Neoprimavlar'', and ''Preven'' (in the United States) but were withdrawn after more effective dedicated progestin-only (levonorgestrel) emergency contraceptive pills with fewer side effects became available.<ref name="Trussell 2014"/> If other more effective dedicated emergency contraceptive pills (levonorgestrel, ulipristal acetate, or mifepristone) are not available, specific combinations of regular combined oral contraceptive pills can be taken in split doses 12&nbsp;hours apart (the Yuzpe regimen), effective up to 72&nbsp;hours after intercourse.<ref name="Trussell 2014"/>

The U.S. [[Food and Drug Administration]] (FDA) approved this [[off-label use]] of certain brands of regular combined oral contraceptive pills in 1997.<ref name="fr 1997"/> As of 2014, there are 26&nbsp;brands of regular combined oral contraceptive pills containing levonorgestrel or norgestrel available in the United States that can be used in the emergency contraceptive Yuzpe regimen,<ref name="Trussell 2014"/> when none of the more effective and better-tolerated options are available.

===Effectiveness===
Ulipristal acetate, and mid-dose mifepristone are both more effective than levonorgestrel, which is more effective than the Yuzpe method.<ref name="Interventions for emergency contrac">{{cite journal | vauthors = Shen J, Che Y, Showell E, Chen K, Cheng L | title = Interventions for emergency contraception | journal = The Cochrane Database of Systematic Reviews | volume = 1 | issue = 1 | pages = CD001324 | date = January 2019 | pmid = 30661244 | pmc = 7055045 | doi = 10.1002/14651858.CD001324.pub6 }}</ref>

The effectiveness of emergency contraception is expressed as a percentage reduction in pregnancy rate for a single use of EC. Using an example of "75% effective", the effectiveness calculation thus: {{blockquote|... these numbers do not translate into a pregnancy rate of 25 percent. Rather, they mean that if 1,000 women have unprotected intercourse in the middle two weeks of their menstrual cycles, approximately 80 will become pregnant. Use of emergency contraceptive pills would reduce this number by 75 percent, to 20 women.<ref name="weismiller">{{cite journal | vauthors = Weismiller DG | title = Emergency contraception | journal = American Family Physician | volume = 70 | issue = 4 | pages = 707–714 | date = August 2004 | pmid = 15338783 |url=http://www.aafp.org/afp/20040815/707.html | access-date = 2006-12-01 | url-status = dead | archive-url=https://web.archive.org/web/20070929100133/http://www.aafp.org/afp/20040815/707.html | archive-date = 2007-09-29 }}</ref>}}

The progestin-only regimen (using levonorgestrel) has an 89% effectiveness.  {{As of|2006}}, the labeling on the U.S. brand Plan B explained this effectiveness rate by stating, "Seven out of every eight women who would have gotten pregnant will not become pregnant."<ref name="Plan B 2006">{{cite web |publisher =[[Food and Drug Administration (United States)|Food and Drug Administration]] |date=August 24, 2006 |title=Plan B label information |url=https://www.fda.gov/cder/foi/label/2006/021045s011lbl.pdf |access-date=2007-07-03 |archive-url=https://web.archive.org/web/20070124182515/https://www.fda.gov/cder/foi/label/2006/021045s011lbl.pdf <!-- Bot retrieved archive --> |archive-date = 2007-01-24}}</ref>

In 1999, a meta-analysis of eight studies of the combined (Yuzpe) regimen concluded that the best point estimate of effectiveness was 74%.<ref name="trussell 1999">{{cite journal | vauthors = Trussell J, Rodríguez G, Ellertson C | title = Updated estimates of the effectiveness of the Yuzpe regimen of emergency contraception | journal = Contraception | volume = 59 | issue = 3 | pages = 147–151 | date = March 1999 | pmid = 10382076 | doi = 10.1016/S0010-7824(99)00018-9 }}</ref> A 2003 analysis of two of the largest combined (Yuzpe) regimen studies, using a different calculation method, found effectiveness estimates of 47% and 53%.<ref name="trussell 2003a">{{cite journal | vauthors = Trussell J, Ellertson C, von Hertzen H, Bigrigg A, Webb A, Evans M, Ferden S, Leadbetter C | display-authors = 6 | title = Estimating the effectiveness of emergency contraceptive pills | journal = Contraception | volume = 67 | issue = 4 | pages = 259–265 | date = April 2003 | pmid = 12684144 | doi = 10.1016/S0010-7824(02)00535-8 }}</ref>

For both the progestin-only and Yuzpe regimens, the effectiveness of emergency contraception is highest when taken within 12 hours of intercourse and declines over time.<ref name="WHO 1998">{{cite journal | vauthors = ((WHO Task Force on Postovulatory Methods of Fertility Regulation)) | title = Randomised controlled trial of levonorgestrel versus the Yuzpe regimen of combined oral contraceptives for emergency contraception. Task Force on Postovulatory Methods of Fertility Regulation | journal = Lancet | volume = 352 | issue = 9126 | pages = 428–433 | date = August 1998 | pmid = 9708750 | doi = 10.1016/S0140-6736(98)05145-9 | s2cid = 54419012 }}</ref><ref>{{cite journal | vauthors =  | title = Counsel women to take ECPs as soon as possible | journal = Contraceptive Technology Update | volume = 20 | issue = 7 | pages = 75–77 | date = July 1999 | pmid = 12295381 }}</ref><ref name="who 1999">{{cite journal | vauthors = (([[World Health Organization|WHO]]/HRP)) | title = Levonorgestrel is more effective, has fewer side-effects, than Yuzpe regimen | journal = Progress in Human Reproduction Research | issue = 51 | pages = 3–5 | year = 1999 | pmid = 12349416 |url=https://www.who.int/reproductive-health/hrp/progress/51/news51_1.en.html#2 | access-date = 2007-07-03 | url-status = dead | archive-url=https://web.archive.org/web/20070422232716/http://www.who.int/reproductive-health/hrp/progress/51/news51_1.en.html#2 | archive-date = 2007-04-22 }}</ref>
The [[World Health Organization]] (WHO) suggested that reasonable effectiveness may continue for up to 120 hours (5 days) after intercourse.<ref name="WHO 2002">{{cite journal | vauthors = von Hertzen H, Piaggio G, Ding J, Chen J, Song S, Bártfai G, Ng E, Gemzell-Danielsson K, Oyunbileg A, Wu S, Cheng W, Lüdicke F, Pretnar-Darovec A, Kirkman R, Mittal S, Khomassuridze A, Apter D, Peregoudov A | display-authors = 6 | title = Low dose mifepristone and two regimens of levonorgestrel for emergency contraception: a WHO multicentre randomised trial | journal = Lancet | volume = 360 | issue = 9348 | pages = 1803–1810 | date = December 2002 | pmid = 12480356 | doi = 10.1016/S0140-6736(02)11767-3 | s2cid = 10340798 }}</ref>

For 10&nbsp;mg of mifepristone taken up to 120 hours (5 days) after intercourse, the combined estimate from three trials was an effectiveness of 83%.<ref name="piaggio 2003">{{cite journal | vauthors = Piaggio G, Heng Z, von Hertzen H, Bilian X, Linan C | title = Combined estimates of effectiveness of mifepristone 10 mg in emergency contraception | journal = Contraception | volume = 68 | issue = 6 | pages = 439–446 | date = December 2003 | pmid = 14698074 | doi = 10.1016/S0010-7824(03)00110-0 }}</ref> A review found that a moderate dose of mifepristone is better than LNG or Yuzpe, with delayed return of menstruation being the main adverse effect of most regimes.<ref name="Interventions for emergency contrac"/>

HRA Pharma changed its packaging information for Norlevo (levonorgestrel 1.5&nbsp;mg, which is identical to many other EHCs) in November 2013 warning that according to studies the drug loses effectiveness in women who weigh more than 75&nbsp;kg (165&nbsp;lb) and is completely ineffective for women who weigh over 80&nbsp;kg (176&nbsp;lb).<ref>{{cite web|url=https://www.motherjones.com/environment/2013/11/plan-b-morning-after-pill-weight-limit-pounds|title=Morning-after pill doesn't work for women over 176 pounds|website=Mother Jones}}</ref><ref>{{cite web|url=http://www.popsci.com/article/science/fyi-why-doesnt-plan-b-work-heavier-women?src=SOC&dom=fb|title=FYI: Why Doesn't Plan B Work For Heavier Women?|website=popsci.com|date=27 November 2013}}</ref> After a review by [[European Medicines Agency]], the statement was deleted from the leaflet. The agency communicated that levonorgestrel is safe and effective method of emergency contraception, regardless of body weight.<ref>{{cite web|title=Emergency contraceptives|date=17 September 2018 |publisher=European Medicines Agency|url=https://www.ema.europa.eu/en/medicines/human/referrals/emergency-contraceptives|access-date=16 May 2022|url-status=live|archive-url=https://web.archive.org/web/20181004224811/https://www.ema.europa.eu/en/medicines/human/referrals/emergency-contraceptives|archive-date=4 October 2018}}</ref>

===Safety===
{{See also|Progestin#Side effects|Progestin#Mood changes}}

The most common side effect reported by users of emergency contraceptive pills was [[nausea]], reported by 14 to 23% of levonorgestrel-only users and 50.5% of Yuzpe regimen users. [[Vomiting]] is much less common and unusual with levonorgestrel-only ECPs (5.6% of levonorgestrel-only users vs 18.8% of 979 Yuzpe regimen users in 1998 WHO trial; 1.4% of 2,720 levonorgestrel-only users in the 2002 WHO trial).<ref name="WHO 1998"/><ref name="WHO 2002"/><ref name="FSRH EC 2012"/> [[Antiemetic|Anti-emetics]] are not routinely recommended with levonorgestrel-only ECPs.<ref name="FSRH EC 2012"/><ref name="WHO SPR 20">{{cite book|author=WHO Department of Reproductive Health and Research|date=December 31, 2004|chapter=Question 20. What can a woman do to prevent nausea and vomiting when taking emergency contraceptive pills (ECPs)?|title=Selected practice recommendations for contraceptive use|edition  =2nd|location=Geneva|publisher=World Health Organization|isbn=978-92-4-156284-3|archive-url=https://web.archive.org/web/20090113014114/http://www.who.int/reproductive-health/publications/spr/spr_q20_prevent_nausea_ecps.html|archive-date=2009-01-13|chapter-url=https://www.who.int/reproductive-health/publications/spr/spr_q20_prevent_nausea_ecps.html}}</ref> If a woman vomits within 2 hours of taking a levonorgestrel-only ECP, she should take a further dose as soon as possible.<ref name="FSRH EC 2012"/><ref name="WHO SPR 21">{{cite book|author=WHO Department of Reproductive Health and Research|date=December 31, 2004|chapter=Question 21. What can a woman do if she vomits after taking emergency contraceptive pills (ECPs)?|title=Selected practice recommendations for contraceptive use|edition  =2nd|location=Geneva |publisher=World Health Organization|isbn=978-92-4-156284-3|archive-url=https://web.archive.org/web/20090113042947/http://www.who.int/reproductive-health/publications/spr/spr_q21_womiting_ecps.html|archive-date=2009-01-13|chapter-url=https://www.who.int/reproductive-health/publications/spr/spr_q21_womiting_ecps.html}}</ref>

Other common side effects (each reported by less than 20% of levonorgestrel-only users in both the 1998 and 2002 WHO trials) were [[abdominal pain]], [[fatigue (physical)|fatigue]], [[headache]], [[dizziness]], and [[mastalgia|breast tenderness]].<ref name="WHO 1998"/><ref name="WHO 2002"/><ref name="FSRH EC 2012"/><ref>{{cite web | title = Morning-after pill | publisher = Mayo Clinic |url=https://www.mayoclinic.org/tests-procedures/morning-after-pill/about/pac-20394730 | access-date = 13 Sep 2020}}</ref> Side effects generally resolve within 24 hours,<ref name="Trussell 2014"/> although temporary disruption of the menstrual cycle is commonly experienced. If taken before ovulation, the high doses of progestogen in levonorgestrel treatments may induce progestogen withdrawal bleeding a few days after the pills are taken.

One study found that about half of women who used levonorgestrel ECPs experienced bleeding within 7 days of taking the pills.<ref name="Raymond 2006">{{cite journal | vauthors = Raymond EG, Goldberg A, Trussell J, Hays M, Roach E, Taylor D | title = Bleeding patterns after use of levonorgestrel emergency contraceptive pills | journal = Contraception | volume = 73 | issue = 4 | pages = 376–381 | date = April 2006 | pmid = 16531171 | doi = 10.1016/j.contraception.2005.10.006 }}</ref> If levonorgestrel is taken after ovulation, it may increase the length of the [[luteal phase]], thus delaying menstruation by a few days.<ref>{{cite journal | vauthors = Gainer E, Kenfack B, Mboudou E, Doh AS, Bouyer J | title = Menstrual bleeding patterns following levonorgestrel emergency contraception | journal = Contraception | volume = 74 | issue = 2 | pages = 118–124 | date = August 2006 | pmid = 16860049 | pmc = 1934349 | doi = 10.1016/j.contraception.2006.02.009 }}</ref> Mifepristone, if taken before ovulation, may delay ovulation by 3–4 days<ref>{{cite journal | vauthors = Gemzell-Danielsson K, Marions L | title = Mechanisms of action of mifepristone and levonorgestrel when used for emergency contraception | journal = Human Reproduction Update | volume = 10 | issue = 4 | pages = 341–348 | date = July–August 2004 | pmid = 15192056 | doi = 10.1093/humupd/dmh027 | doi-access = free }}</ref> (delayed ovulation may result in a delayed menstruation). These disruptions only occur in the cycle in which ECPs were taken; subsequent cycle length is not significantly affected.<ref name="Raymond 2006" /> If a woman's menstrual period is delayed by two weeks or more, it is advised that she take a [[pregnancy test]].<ref name="ACOG 2010" /> (Earlier testing may not give accurate results.)

Existing pregnancy is not a [[contraindication]] in terms of safety, as there is no known harm to the woman, the course of her pregnancy, or the fetus if progestin-only or combined emergency contraception pills are accidentally used, but EC is not [[indication (medicine)|indicated]] for a woman with a known or suspected pregnancy because it is not effective in women who are already pregnant.<ref name="Trussell 2014"/><ref name="AAP 2005">{{cite journal | vauthors = ((American Academy of Pediatrics Committee on Adolescence)) | title = Emergency contraception | journal = Pediatrics | volume = 116 | issue = 4 | pages = 1026–1035 | date = October 2005 | pmid = 16147972 | pmc = 1197142 | doi = 10.1542/peds.2005-1877 }}</ref><ref name="Grimes 2002">{{cite journal | vauthors = Grimes DA, Raymond EG | title = Emergency contraception | journal = Annals of Internal Medicine | volume = 137 | issue = 3 | pages = 180–189 | date = August 2002 | pmid = 12160366 | doi = 10.7326/0003-4819-137-3-200208060-00010 | s2cid = 19236983 }}</ref><ref name="ACOG 2010">{{cite journal | vauthors = ((American College of Obstetricians and Gynecologists)) | title = ACOG Practice Bulletin No. 112: Emergency contraception | journal = Obstetrics and Gynecology | volume = 115 | issue = 5 | pages = 1100–1109 | date = May 2010 | pmid = 20410799 | doi = 10.1097/AOG.0b013e3181deff2a | doi-access = free }}</ref><ref name="FDA Plan B Rx to OTC switch med review">{{cite web|author=FDA Center for Drug Evaluation and Research|date=August 22, 2006|title=Plan B Rx to OTC switch Medical Reviews|location=Beltsville, Md.|publisher=Food and Drug Administration|pages=32–7, 133–77|url=http://www.accessdata.fda.gov/drugsatfda_docs/nda/2006/021045s011_Plan_B__MedR.pdf|access-date=2006-12-13}}</ref><ref name="WHO MEC 2009">{{cite book|author=WHO Department of Reproductive Health and Research|year=2009|chapter=Emergency contraceptive pills (ECPs)|title=Medical eligibility criteria for contraceptive use|edition  =4th|location=Geneva|publisher=World Health Organization|isbn=978-92-4-156388-8|page=63|chapter-url=http://whqlibdoc.who.int/publications/2010/9789241563888_eng.pdf}}</ref><ref name="UK MEC 2009">{{cite web|author1=RCOG Faculty of Sexual|author2=Reproductive Healthcare|year=2009|title=UK medical eligibility criteria for contraceptive use: Emergency contraception|location=London|publisher=Royal College of Obstetricians and Gynaecologists|pages=107–115|url=http://www.fsrh.org/pdfs/UKMEC2009.pdf|access-date=2012-04-30|archive-date=2016-03-03|archive-url=https://web.archive.org/web/20160303222644/http://www.fsrh.org/pdfs/UKMEC2009.pdf|url-status=dead}}</ref><ref name="US MEC 2010">{{cite journal | vauthors = ((CDC Division of Reproductive Health)) | title = U S. Medical Eligibility Criteria for Contraceptive Use, 2010 | journal = MMWR. Recommendations and Reports | volume = 59 | issue = RR-4 | pages = 1–86 | date = June 2010 | pmid = 20559203 |url=https://www.cdc.gov/mmwr/pdf/rr/rr5904.pdf }}</ref><ref name="Davidoff 2006">{{cite journal | vauthors = Davidoff F, Trussell J | title = Plan B and the politics of doubt | journal = JAMA | volume = 296 | issue = 14 | pages = 1775–1778 | date = October 2006 | pmid = 17032991 | doi = 10.1001/jama.296.14.1775 }}</ref>

The [[World Health Organization]] (WHO) lists no medical condition for which the risks of emergency contraceptive pills outweigh the benefits.<ref name="WHO MEC 2009"/> The [[American Academy of Pediatrics]] (AAP) and experts on emergency contraception have concluded that progestin-only ECPs are preferable to combined ECPs containing estrogen for all women, and particularly those with a history of blood clots, stroke, or migraine.<ref name="Trussell 2014"/><ref name="AAP 2005"/><ref name="Grimes 2002"/>

There are no medical conditions in which progestin-only ECPs are contraindicated.<ref name="Trussell 2014"/><ref name="AAP 2005"/><ref name="Grimes 2002"/><ref name="ACOG 2010"/><ref name="FDA Plan B Rx to OTC switch med review"/><ref name="WHO MEC 2009"/><ref name="UK MEC 2009"/> Current [[venous thrombosis|venous thromboembolism]], current or history of [[breast cancer]], [[inflammatory bowel disease]], and [[acute intermittent porphyria]] are conditions where the advantages of using emergency contraceptive pills generally outweigh the theoretical or proven risks.<ref name="UK MEC 2009"/>

ECPs, like all other contraceptives, reduce the absolute risk of [[ectopic pregnancy]] by preventing pregnancies and there is no increase in the relative risk of ectopic pregnancy in women who become pregnant after using progestin-only ECPs.<ref name="Trussell 2014"/><ref name="WHO 2010">{{cite web|author=UNDP/UNFPA/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP)|date=March 25, 2010|title=Fact sheet on the safety of levonorgestrel-alone emergency contraceptive pills (LNG ECPs)|location=Geneva|publisher=World Health Organization|url=http://whqlibdoc.who.int/hq/2010/WHO_RHR_HRP_10.06_eng.pdf}}{{blockquote|Can LNG ECPs cause an abortion?<br />LNG ECPs do not interrupt an established pregnancy or harm a developing embryo.<sup>15</sup> The evidence available to date shows that LNG ECP use does not prevent a fertilized egg from attaching to the uterine lining. The primary mechanism of action is to stop or disrupt ovulation; LNG ECP use may also prevent the sperm and egg from meeting.<sup>16</sup>}}</ref><ref name="Cleland 2010">{{cite journal | vauthors = Cleland K, Raymond E, Trussell J, Cheng L, Zhu H | title = Ectopic pregnancy and emergency contraceptive pills: a systematic review | journal = Obstetrics and Gynecology | volume = 115 | issue = 6 | pages = 1263–1266 | date = June 2010 | pmid = 20502299 | pmc = 3903002 | doi = 10.1097/AOG.0b013e3181dd22ef }}</ref>