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Emergency contraception (EC) (also known as Emergency Birth Control (EBC), the morning-after pill, or postcoital contraception) refers to measures that, if taken after sex, may prevent a pregnancy.

Forms of EC include:

• Emergency contraceptive pills—referred to simply as "emergency contraception," "ECPs," or "ECs", or "morning-after pills"—are drugs that act both to prevent ovulation or fertilisation and possibly post-fertilisation implantation of a blastocyst (embryo). ECPs are distinct from chemical abortion methods that act after implantation has occurred.
• Intrauterine devices (IUDs)—usually used as a primary contraception method, but sometimes used as emergency contraception.

As its name implies, EC is intended for use in occasional cases only, in the event of a failure of primary means of contraception. Since EC methods act before implantation, they are medically and legally considered to be forms of contraception. Some pro-life groups define pregnancy as beginning with fertilisation, and therefore consider EC to be an abortifacient. These claims remain controversial; see below.

ECPs

Emergency contraceptive pills may contain higher doses of the same hormones (estrogens and progestins) found in regular oral contraceptive pills. Taken after unprotected sexual intercourse, such higher doses may prevent pregnancy from occurring. Mifepristone is another kind of ECP, but it is considered an anti-hormonal drug, and does not contain estrogen or progestins.

The phrase "morning-after pill" is figurative; ECP's are licensed for use up to 72 hours after sexual intercourse.

Types of ECPs

The progestin-only method uses the progestin levonorgestrel in a dose of 1.5 mg, either as two 750 μg doses 12 hours apart, or more recently, as a single dose. Progestin-only EC is available as a dedicated emergency contraceptive product in the U.S. and Canada as Plan B, in the U.K. as Levonelle, in France and India as NorLevo, and in 40 nations including Mexico, New Zealand, Australia, all of Eastern Europe, and most developing countries as Postinor-2.

The combined or Yuzpe regimen uses large doses of both estrogen and progestin, taken as two doses at 12-hour intervals. This method is now believed to be less effective and less well-tolerated than the progestin-only method.

"Dedicated products" such as Plan B, Levonelle and NorLevo are specifically designed and marketed as emergency contraceptive pills. It is also possible to obtain the same dosage of hormones, and therefore the same effect, by taking a large number of regular progestin-only oral contraceptive pills. For example, 40 Ovrette pills is equal to Plan B.

The drug mifepristone may be used either as an ECP or as an abortifacient, depending on whether it is used before or after implantation. In the USA, it is most commonly used in 200- or 600-mg doses as an abortifacient, but in China it is commonly used as an ECP. As ECP, a low dose of mifepristone is slightly less effective than higher doses, but has fewer side effects. As of 2000, the smallest dose available in the USA was 200 mg. A review of studies in humans concluded that the contraceptive effects of the 10-mg dose are due to its effects on ovulation, but understanding of the mechanism of action remains incomplete. Higher doses of mifepristone can disrupt implantation and, unlike levonorgestrel, mifepristone is effective in terminating established pregnancies.

Effectiveness of ECPs

The effectiveness of emergency contraception is calculated based on projected probabilities of conception, and expressed as a percentage reduction in probable pregnancy rate for a single use of EC. Clinical placebo-controlled trials that could give a true measure of effectiveness for EC would be unethical, so the effectiveness percentage must be estimated. The estimates are calculated based on an 8% pregnancy rate mid-cycle after a single act of intercourse. For example, if 100 women had unprotected sex mid-cycle, 8 of them would statistically become pregnant. If they all took EC, this number might be reduced to 2. The reduction of the odds from 8 to 2 translates to 75% effectiveness; that is, a 75% reduction in the relative risk of pregnancy. But it does not mean that 25% of EC users become pregnant, or that 75% do not. The percentage reflects the reduction of the odds of pregnancy for a single use of EC. The annual failure rate of EC is estimated at 19-38%, which means that over the course of a year, EC averages to less effective than it does for a single use.

Levonorgestrel ECP's may prevent at least 50% of expected pregnancies among women who take them correctly; the current product labelling states that they can prevent at least 75% of expected pregnancies. Until 1998, the Yuzpe regime of ECPs was believed to reduce expected pregnancies by about 75%, but is now believed to reduce only 57%.

The effectiveness of emergency contraception is highest when taken within 12 hours of intercourse and declines over time. The limit of 72 hours is based on a study by the World Health Organization(WHO). A subsequent WHO study has suggested that reasonable effectiveness continues for up to 120 hours (5 days). However, many doctors (particularly in the U.K.) advise use of an IUD rather than ECP's for emergency contraception between 72 and 120 hours.

Because women in clinical trials of EC are likely to face higher pregnancy risk than the general population, the estimated number of pregnancies averted by treatment may be overestimated. Variables which can affect EC effectiveness other than the 8% "adjusted day of unprotected intercourse" include regularity of menstrual cycle, recent hormone use such as oral contraceptives, breastfeeding, and the number of acts of unprotected intercourse. The effectiveness estimates of emergency contraception may also be overestimated because the calendar method of fertility awareness--used in trials to estimate the number of fertile women and the number of expected pregnancies--is not highly accurate. In an analysis of hormone blood test data taken from trial subjects in an EC effectiveness study, far fewer of the women surmised to be fertile were actually fertile.

Controversy in estimating EC effectiveness

The original method of calculating the failure rate of EC was to divide the number of observed pregnancies by the number of women treated. This produced failure rates of below 1% for diethylstilbestrol and 0.16-5% for combined estrogen-progestin. In 1991, researchers argued in an article called "Postcoital contraception: Myth or reality?" that these failure rates were serious underestimates, because 100 women is unlikely to equal 100 pregnancies. They reconfigured the failure rates in a meta-analysis of the studies, which used conception probabilities to determine how many women in an average 100 are at risk of pregnancy, and concluded that the failure rates for EC ranged from 44-100% for combined estrogen-progestin. After that, the published failure rates of EC were calculated using conception probabilities based on the calendar method.

Abortion rates and EC

The availability of ECP's has not been shown to lower abortion rates. In France, Sweden, and the U.K.—where EC has been available for more than a decade—the abortion rate was stable or higher during that time period. A study conducted to determine if distribution of free, advance supplies of EC to large numbers of women in Scotland could lower abortion rates concluded that it did not. According to EC expert Anna Glasier, EC is "better than nothing" and "worth the fuss... if you are a woman who has had unprotected sex," because "it will work in some women some of the time," but is not a useful public health measure. She stated that "if you are looking for an intervention that will reduce abortion rates, emergency contraception may not be the solution, and perhaps you should concentrate most on encouraging people to use contraception before or during sex." A randomized controlled trial of 2000 women in China compared women with advance access to EC to women without access, and noted that the pregnancy rate was the same between the two groups. The study observed that "...providing EC in advance increases use, but there is no direct evidence that it reduces unintended pregnancy" and concluded that EC may not lower abortion rates.

ECPs as a birth control method

Emergency contraception is not recommended for use as an ongoing method of contraception, because it is not as effective as other methods of contraception; its highest estimated efficacy as an annual method is approximately equal to the annual efficacy of coitus interruptus. It also does not protect against sexually transmitted infections. It is intended for use as a back-up when other means of contraception have failed—for example, if a woman has forgotten to take a birth control pill or when a condom is torn during sex.

Contraindications & Interactions

Plan B and Yuzpe should not be used by women who are already pregnant, because they are not effective after implantation.

Because they contain estrogen, combined estrogen-progestin emergency contraception (Yuzpe regimen) pills should not be used by women with a history of heart attack, stroke, or blood clots, or patients with severe liver disease or the very rare condition of porphyria.

The herbal preparation of St John's wort and some enzyme-inducing drugs (e.g. anticonvulsants or rifampicin) may reduce the effectiveness of ECP, and a larger dose may be required. (Levonorgestrel 1500mcg initial dose and an extra 750 mcg after 12 hours).

Side effects

The most common side effects of emergency contraception pills are nausea, abdominal pain, fatigue, headache, dizziness, vomiting, and mastalgia. These side effects normally resolve within 24 hours. The rate of these effects is less for progestin-only pills compared to combined pills (only 23% of progestin-only users experience nausea, whereas 50% of combined pill users do). The presence of estrogen in combined ECPs is responsible for the increased incidence of nausea and vomiting. Antiemetics may be prescribed for both methods. If vomiting occurs within an hour after taking ECPs, it may be necessary to repeat the dose.

Temporary disruption of the menstrual cycle is also common and may manifest as early or late periods, spotting or breakthrough bleeding, and (less commonly) missed periods. The primary mechanism of EC is delaying ovulation. Menstruation occurs, on average, 14 days after ovulation, so delayed ovulation results in delayed menstruation. Suppression of ovulation may cause anovulatory bleeding, which could manifest as an early period.

Ectopic pregnancy

Ectopic pregnancies account for approximately 2% of reported pregnancies. Up to 10% of pregnancies reported in clinical studies of routine use of progestin-only contraceptives are ectopic. Progestins can slow the intratubal migration of fertilized ovum, which may explain the possible increased risk. A history of ectopic pregnancy need not be considered a contraindication to use of levonorgestrel EC, but consumers and health providers should be alert to the possibility of an ectopic pregnancy in women who become pregnant or complain of lower abdominal pain after taking levonorgestrel EC. Following the discovery that one in twenty pregnancies resulting after Levonelle failure were ectopic, the product labelling was changed and an update was issued to physicians in the UK to warn patients of the risk. Ectopic pregnancy is a medical emergency which can be fatal.

Postmarketing Surveillance

The postmarketing surveillance for Plan B and Levonelle reports adverse reactions which are mostly nonserious, and which are already described in the product labeling. Serious adverse reactions included:

• Three cases of convulsions, including a grand mal seizure in a patient with no history of epilepsy. The other two cases occurred in epileptics, and are surmised to be attributable to drug-interaction. (Antiepileptic drugs may alter the metabolism of most hormonal methods of contraception).

• Ten cases of hypersensitivity reaction, seven of which were considered life-threatening. The current Plan B labelling does not address hypersensitivity reactions.

• 28 cases of ectopic pregnancy, 15 of them life-threatening.

Confirmation of Results

A pregnancy test is the only reliable way to confirm whether or not EC has been effective. EC can cause menstrual changes that appear similar to early signs of pregnancy, and some doctors therefore advise all women who take EC to take a pregnancy test afterwards to get confirmation of the results.

Pregnancy tests will not give positive results until after an embryo has implanted, which occurs six to twelve days after ovulation. The most sensitive tests can detect pregnancy the day after implantation, so the earliest a positive result would be seen would be one week after intercourse (assuming intercourse occurred on the day of ovulation). Sperm life of up to five days is considered normal, and less sensitive tests may not detect pregnancy until three to four days after implantation. So a pregnancy test may give false negatives up to three weeks after intercourse (five days between intercourse and ovulation, twelve days between ovulation and implantation, four days between implantation and detectable levels of the pregnancy hormone hCG).

Risky Sex

Whether or not EC use is associated with increases in sexual risk taking behavior is unclear--some studies show a correlation; some do not. Between 1999 and 2004 in Sweden, the use of emergency contraceptive pills by female university students more than doubled. During the study period, there was a trend towards more risky sexual behavior with more sexual partners, more unprotected first-date intercourse, and more self-reported sexually transmitted infections. Teen sexually transmitted infections have increased in Sweden since emergency contraception has been available over the counter. During this same period, Sweden has undergone a decrease in sex education, economic stagnation, and increases in drug use and school non-attendance, which may play a role in the increases. At least one study has found that when emergency contraception is available, the incidence of unprotected sex does not increase. In the US, the issue has been hotly debated with regards to whether EC should be available over-the-counter for teens. FDA official Janet Woodcock claimed that easy access for teens would result in teen promiscuity, but a US study has shown that teens are not more likely to engage in unprotected sex than young adults are, when both have advance access to EC.

Intrauterine device used for emergency contraception

An alternative to emergency contraceptive pills is the copper-T intrauterine device (IUD) which can be used up to 5 days after unprotected intercourse to prevent pregnancy. Insertion of an IUD is more effective than use of Emergency Contraceptive Pills - pregnancy rates when used as emergency contraception are the same as those of normal IUD use. IUDs may then be left in place following the subsequent menstruation to provide ongoing contraception (3-10 years depending upon type).

History

Interest in hormones as postcoital contraceptives originated several decades ago, with the first published study on the subject appearing in 1967. A few different drugs were studied, with a focus on high-dose estrogens, and it was originally hoped that postcoital contraception would prove viable as an ongoing contraceptive method. The first FDA-approved method (approved in 1973) was a five-day treatment with diethylstilbestrol (DES), which was also used internationally. Later in 1970s, the Yuzpe regimen was developed by AA Yuzpe (1974); progestin-only postcoital contraception was investigated (1975); and the copper IUD was first studied for use as emergency contraception (1975). Danazol was tested in the early 1980s in the hopes that it would have fewer side effects than Yuzpe, but was found to be ineffective.

The Yuzpe regimen became the standard course of treatment for postcoital contraception, and several dedicated products were produced. After the WHO conducted a large trial comparing Yuzpe and levonorgestrel in 1998, these products were gradually withdrawn from the market (Preven in the United States discontinued May 2004, Schering PC4 in the UK discontinued October 2001, and Tetragynon in France).

EC and sexual assault

Before EC was used in the general population or defined as "emergency contraception," it was used, beginning in the 1960s and 70s, specifically as a treatment for victims of sexual assault. Although EC is in wide use as an option for victims of sexual assault, some researchers believe it is underutilized as a public health measure. Abortions because of rape account for less than one percent of all annual abortions.

Controversy

Emergency contraception, implantation, and abortion politics

A number of studies in the 1970s and 80s concluding that emergency contraception could cause changes in the endometrium, and thus preventing implantation of an early stage embryo in the uterus, led many pro-life advocates, who widely believe that pregnancy begins at fertilisation, to oppose ECPs as an abortifacient.

In recent years--especially in light of U.S. controversy over this possibility--the scientific community has begun to critically reevaluate the claim, introducing doubt into the argument that ECPs prevent implantation. Recent studies in rats and monkeys have shown that post-ovulatory use of progestin-only and combined ECPs do not have any effect on pregnancy rates. Studies in humans have shown that the rate of ovulation suppression is approximately equal to the effectiveness of emergency contraceptive pills, suggesting that might be the only mechanism by which they prevent pregnancy.

However, these studies have also shown that, in women who ovulate despite taking ECP before ovulation, there are changes in certain hormones such as progesterone and in the length of luteal phase. These secondary changes might inhibit implantation in cases where fertilization occurs despite ECP use. Because of the difficulty of studying pre-implanted embryos inside the uterus and fallopian tubes, both sides of this debate concede that completely proving or disproving the theory may be impossible.

The Food and Drug Administration recently stopped its practice of referring to all three mechanisms in its publications on emergency contraception. However, the approved box design for Plan B still carries a notification that it may prevent implanation.

When used as a regular method of contraception, IUDs have been proven to act primarily through spermicidal and ovicidal mechanisms, but it is theoretically possible that these same mechanisms are also harmful to pre-implanted embryos.

Hormonal progestin-only and combined estrogen-progestin emergency contraceptives such as Yuzpe regimen or Plan B are different from the anti-hormonal drug mifepristone (also known as Mifeprex and RU-486), an abortifacient which can induce abortion if taken after implantation. Yuzpe and progestin-only emergency contraception will have no effect if taken after implantation.

United States legal and ethical controversies

• A great deal of controversy accompanied the FDA approval of over-the-counter access to Plan B. The AMA, the American Academy of Family Physicians, the American College of Obstetricians and Gynecologists, the American Academy of Pediatrics, and other leading U.S. medical organizations all supported OTC access. An advisory committee to the FDA recommended that Plan B be made available over the counter in 2003. In 2004, the FDA refused the advisory board's strong recommendation and prohibited over-the-counter sale, citing insufficient evidence that ECPs could be used safely by adolescents without medical supervision. Reproductive rights supporters accused the FDA of basing the decision on political pressure from the pro-life lobby. A pro-life spokesman lauded the FDA's decisison as a protection for women's health, and pointed out that EC is 50 times stronger than oral contraceptives, which require a prescription. The Center for Reproductive Rights then filed a lawsuit regarding the approval process, and deposed FDA officials. In one deposition, a senior FDA scientist testified that she was told by Deputy FDA Commissioner Janet Woodcock that Plan B needed to be rejected "to appease the administration's constituents", but that it could be approved later. Woodcock denies that she said this, and testified that she "was not aware of any political pressure." In 2005, a study was published demonstrating that direct access to ECPs without a prescription doesn't result in fewer unintended pregnancies than controlled access via prescription. In 2006, after the 2004 Presidential election, the FDA approved over-the-counter access to Plan B for women 18 years of age and older.

• A Massachusetts law that went into effect on 14 December, 2005, requires all hospitals in the state to provide emergency contraception to any "female rape victim of childbearing age" including Catholic Hospitals who oppose the provision of emergency contraception. In a letter criticizing the joint UN/WHO Inter-agency Field Manual on Reproductive Health in Refugee Situations, the Catholic Church explains its belief that emergency contraception, along with IUDs and hormonal contraception, cannot be considered "solely contraceptive because in the case of effective fertilisation a chemical abortion would be carried out during the first days of pregnancy." The Catholic position on family planning is explained further in Ethical and Religious Directives for Catholic Health Care Services. Because of this expressed moral stance against emergency contraception, the Massachusetts Catholic Conference opposed this law, stating interference with religious freedom.

• Barr Laboratories, manufacturer of Plan B, sells its product at an exclusive preferential discount to Planned Parenthood. Planned Parenthood has vocally supported ECPs, and distributes large numbers of them without disclosing their financial conflict of interest.

• In isolated instances across the United States, pharmacists have refused to give women emergency contraception even with a legal prescription. In addition, Wal-Mart— the nations' fifth largest distributor of pharmaceuticals—refused to stock EC, beginning with Preven in 1999. They reversed their decision in 2006, but continued to allow individual pharmacists in their employ to refuse to dispense EC, under the Conscience Clause (medical).

• In 2002, the FDA's Division of Drug Marketing, Advertising, and Communications sent a warning letter to the license-holder of Plan B, citing their direct-to-consumer ads as "false, lacking in fair balance or otherwise misleading, in violation of the Federal Food, Drug, and Cosmetic Act." FDA noted, "Specifically, the direct-to-consumer print and radio ads overstate efficacy, fail to convey important limitations on use, and minimize important information about risks associated with the use of Plan B. As a result, the ads raise significant public health and safety concerns."

International availability

United Kingdom

In 1984, Schering PC4 was approved. Levonelle was launched in 2000; and became available without prescription in 2001 for women of age 16 and older. This was challenged by a pro-life group, but the High Court of Justice of England and Wales let the rule stand in April 2002. In 2005, Levonelle One Step--a new regimen of one pill instead of two--replaced Levonelle.

United States

DES and EE (ethinyl estradiol) were approved in 1975, and are no longer used as emergency contraception. Preven was approved in 1998, and pulled from the market in 2004. Plan B was approved for prescription-only use in 1999. In 2006, Plan B was approved for over-the-counter access, but only for women 18 years and older.

Canada

In April, 2005, Canada approved over-the-counter sales of Plan B.

France

In January 2000, France decided to dispense emergency contraception in junior and high schools by school nurses without prescription, because of high rates of undesired pregnancies among teenaged girls. After strong opposition from the Roman Catholic Church, and much debate around the fact the teenager could later suffer from the doubt of not knowing whether fertilization had occurred or not, the decision was overruled by a court in July 2000. The French parliament changed the relevant law in October 2000 and now school nurses are again able to dispense the drugs. The emergency contraception pill NorLevo is now available in France without prescription, without parent authorization, and free of charge for teenagers under the age of 18 since January 9, 2002.

New Zealand

In 1996, EC was approved for over the counter access, with the support of the Ministry of Health. The New Zealand Medical Association expressed serious reservations about OTC access to "such a powerful medication, because it could be used as normal contraception." Schering New Zealand, manufacturer of PC4, also opposed consumption of their product without medical consultation, because "...the pills may be used repeatedly and incorrectly, putting women at risk of very high dose contraception."

Other Countries

Levonorgestrel emergency contraception is available in 101 countries, and is available without prescription in 33 of them, including: Albania, Australia, Belgium, Benin, Bulgaria, Cameroon, Chile, China, Colombia, Congo, Croatia, Denmark, Estonia, Finland, French Polynesia, Gabon, Ghana, Greece, Guinea-Conakry, Iceland, India, Israel, Ivory Coast, Jamaica, Latvia, Lithuania, Madagascar, Mali, Mauritania, Mauritius, Morocco, Mexico, Netherlands, Norway, Portugal, Romania, Senegal, South Africa, Sri Lanka, Sweden, Switzerland, Togo, Tunisia, Turkey, Italy and Uruguay.

In Ireland it is available without restriction, but is not available over-the counter and requires a visit to a doctor of family-planning clinic.

Footnotes

1. A minority view within the medical community, along with many pro-life advocates, argue for a different definition of pregnancy; see Controversy section for more detail.
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External links

• The Morning-After Pill Conspiracy – A grassroots feminist coalition whose members have given out the pill in defiance of the government's refusal to put Plan B over-the-counter. Members of this coalition are involved in a lawsuit with the Center for Reproductive Rights, Tummino v. Crawford, against the FDA alleging sex discrimination.
• The Emergency Birth Control Organization – Information on Emergency Contraception
• Emergency Contraception Resource Center from the Association of Reproductive Health Professionals
• The Limits of Conscientious Objection - May Pharmacists Refuse to Fill Prescriptions for Emergency Contraception? Julie Cantor,J.D.,and Ken Baum,M.D.,J.D. NEJM, November 4, 2004
• The case of the conscientious pharmacist - Don Herzog
• Center for Policy Alternatives – Emergency Contraception Policy Brief and Model Legislation
• Not-2-Late.com, the Emergency Contraception Website
• American Society for Emergency Contraception
• Go 2 EC – Emergency Contraception News
• Planned Parenthood – information on emergency contraception
• Plan B
• Original documents & Congressional report on FDA refusal of OTC Plan B application
• Emergency Contraception Information– Information on Emergency Contraception
• Health Politics: Women and Plan B

• Chemical contraception
• Hormonal contraception