Emergency contraception

Emergency contraception are birth control measures that may be used after sexual intercourse to prevent pregnancy. Emergency contraception has not been shown to affect the rates of abortion within a country.
There are different forms of EC. Emergency contraceptive pills —sometimes simply referred to as emergency contraceptives or the morning-after pill—are medications intended to disrupt or delay ovulation or fertilization, which are necessary for pregnancy. ECPs and abortion pills are not the same. Intrauterine devices —usually used as a primary contraceptive method—are sometimes used as the most effective form of emergency contraception. However, use of IUDs for emergency contraception is relatively rare.

Emergency contraceptive pills

Emergency contraceptive pills are taken after unprotected sexual intercourse or breakage of a condom.


A variety of types of emergency contraceptive pills are available: combined estrogen and progestin pills, progestin-only pills, and antiprogestin pills. Progestin-only and antiprogestin pills are available specifically packaged for use as emergency contraceptive pills. Emergency contraceptive pills originally contained higher doses of the same hormones found in regular combined oral contraceptive pills. Combined estrogen and progestin pills are no longer recommended as dedicated emergency contraceptive pills, but certain regular combined oral contraceptive pills have also been shown to be effective as emergency contraceptive pills.
Progestin-only emergency contraceptive pills contain levonorgestrel, either as a single tablet, effective up to 72 hours after intercourse. Progestin-only ECPs are sold under many different brand names. Progestin-only ECPs are available over-the-counter in many countries, from a pharmacist without a prescription, and available with a prescription in some other countries.
The antiprogestin ulipristal acetate is available as a micronized emergency contraceptive tablet, effective up to 120 hours after intercourse. Ulipristal acetate ECPs developed by HRA Pharma are available over the counter in Europe and by prescription in over 50 countries under the brand names ellaOne, ella, Duprisal 30, Ulipristal 30, and UPRIS.
The antiprogestin mifepristone is available in five countries as a low-dose or mid-dose emergency contraceptive tablet, effective up to 120 hours after intercourse. Low-dose mifepristone ECPs are available by prescription in Armenia, Russia, Ukraine, and Vietnam and from a pharmacist without a prescription in China. Mid-dose mifepristone ECPs are available by prescription in China and Vietnam.
Combined estrogen and progestin pills used to be available as dedicated emergency contraceptive pills under several brand names: Schering PC4, Tetragynon, Neoprimavlar, and Preven but were withdrawn after more effective dedicated progestin-only emergency contraceptive pills with fewer side effects became available. If other more effective dedicated emergency contraceptive pills are not available, specific combinations of regular combined oral contraceptive pills can be taken in split doses 12 hours apart, effective up to 72 hours after intercourse.
The U.S. Food and Drug Administration approved this off-label use of certain brands of regular combined oral contraceptive pills in 1997. As of 2014, there are 26 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, when none of the more effective and better tolerated options are available.


Ulipristal acetate, and mid-dose mifepristone are both more effective than levonorgestrel, which is more effective than the Yuzpe method.
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:
... 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.

The progestin-only regimen has an 89% effectiveness. , 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."
In 1999, a meta-analysis of eight studies of the combined regimen concluded that the best point estimate of effectiveness was 74%. A 2003 analysis of two of the largest combined regimen studies, using a different calculation method, found effectiveness estimates of 47% and 53%.
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.
The World Health Organization suggested that reasonable effectiveness may continue for up to 120 hours after intercourse.
For 10 mg of mifepristone taken up to 120 hours after intercourse, the combined estimate from three trials was an effectiveness of 83%. 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.
HRA Pharma changed its packaging information for Norlevo in November 2013 warning that the drug loses effectiveness in women who weigh more than 165 pounds and is completely ineffective for women who weigh over 176 pounds.


The most common side effect reported by users of emergency contraceptive pills was nausea. Anti-emetics are not routinely recommended with levonorgestrel-only ECPs. If a woman vomits within 2 hours of taking a levonorgestrel-only ECP, she should take a further dose as soon as possible.
Other common side effects were abdominal pain, fatigue, headache, dizziness, and breast tenderness. Side effects generally resolve within 24 hours, 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. If levonorgestrel is taken after ovulation, it may increase the length of the luteal phase, thus delaying menstruation by a few days. Mifepristone, if taken before ovulation, may delay ovulation by 3–4 days. These disruptions only occur in the cycle in which ECPs were taken; subsequent cycle length is not significantly affected. If a woman's menstrual period is delayed by two weeks or more, it is advised that she take a pregnancy test.
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 indicated for a woman with a known or suspected pregnancy because it is not effective in women who are already pregnant.
The World Health Organization lists no medical condition for which the risks of emergency contraceptive pills outweigh the benefits. The American Academy of Pediatrics 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.
There are no medical conditions in which progestin-only ECPs are contraindicated. Current venous thromboembolism, current or past 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.
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.


The herbal preparation of St John's wort and some enzyme-inducing drugs may reduce the effectiveness of ECP, and a larger dose may be required, especially in women who weigh more than 165 lbs.

Intrauterine device

A more effective alternative to emergency contraceptive pills is the copper-T intrauterine device which is generally recommended 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 with normal IUD use. Unlike emergency contraceptive pills, which work by delaying ovulation, the copper-T IUD works by interfering with sperm motility. Therefore, the copper IUD is equally effective as emergency contraception at all weight ranges. IUDs may be left in place following the subsequent menstruation to provide ongoing contraception for as long as desired.

As regular contraception

One brand of levonorgestrel pills was marketed as an ongoing method of postcoital contraception. However, with typical use, failure rates are expected to be higher than with use of other birth control methods.
ECPs are generally recommended for backup or "emergency" use—for example, if a woman has forgotten to take a birth control pill or when a condom is torn during sex. However, for individuals facing reproductive coercion, who are not able to use regular birth control, repeated use of EC pills may be the most viable option available.

High risk sex and abortion

Making ECPs more widely available does not increase sexual risk-taking. While they are effective for individuals who use them in a timely fashion, availability of EC pills does not appear to decrease abortion rates at the population level.
In 2012 the American Academy of Pediatrics stated: "Despite multiple studies showing no increased risk behavior and evidence that hormonal emergency contraception will not disrupt an established pregnancy, public and medical discourse reflects that personal values of physicians and pharmacists continue to affect emergency-contraception access, particularly for adolescents."

EC and sexual assault

Beginning in the 1960s, women who had been sexually assaulted were offered DES. Currently, the standard of care is to offer ulipristal or prompt placement of a copper IUD which is the most effective forms of EC. However, adherence to these best practices varies by emergency department. Before these EC options were available, pregnancy rates among females of child-bearing age who had been raped were around 5%. Although EC is recommended following sexual assault, room for improvement in clinical practice remains.

Mechanism of action

The primary mechanism of action of progestogen-only emergency contraceptive pills is to prevent fertilization by inhibition of ovulation. The best available evidence is that they do not have any post-fertilization effects such as the prevention of implantation. The U.S. FDA-approved labels and European EMA-approved labels levonorgestrel emergency contraceptive pills say they may cause endometrial changes that discourage implantation. Daily use of regular oral contraceptive pills can alter the endometrium, but the isolated use of a levonorgestrel emergency contraceptive pill does not have time to alter the endometrium.
In March 2011, the International Federation of Gynecology and Obstetrics issued a statement that: "review of the evidence suggests that LNG ECPs cannot prevent implantation of a fertilized egg. Language on implantation should not be included in LNG ECP product labeling." In June 2012, a New York Times editorial called on the FDA to remove from the label the unsupported suggestion that levonorgestrel emergency contraceptive pills inhibit implantation. In November 2013, the European Medicines Agency approved a change to the label for HRA Pharma's NorLevo saying it cannot prevent implantation of a fertilized egg.
Progestogen-only emergency contraceptive does not appear to affect the function of the Fallopian tubes or increase the rate of ectopic pregnancies.
The primary mechanism of action of progesterone receptor modulator emergency contraceptive pills like low-dose and mid-dose mifepristone and ulipristal acetate is to prevent fertilization by inhibition or delay of ovulation. One clinical study found that post-ovulatory administration of ulipristal acetate altered the endometrium, but whether the changes would inhibit implantation is unknown. The European EMA-approved labels for ulipristal acetate emergency contraceptive pills do not mention an effect on implantation, but the U.S. FDA-approved label says: "alterations to the endometrium that may affect implantation may also contribute to efficacy."
The primary mechanism of action of copper-releasing intrauterine devices as emergency contraceptives is to prevent fertilization because of copper toxicity to sperm and ova. The very high effectiveness of copper-releasing IUDs as emergency contraceptives implies that they must also prevent some pregnancies by post-fertilization effects such as prevention of implantation.


In 1966, gynecologist John McLean Morris and biologist Gertrude Van Wagenen at the Yale School of Medicine reported the successful use of oral high-dose estrogen pills as post-coital contraceptives in women and rhesus macaque monkeys, respectively. 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 widely used methods were five-day treatments with high-dose estrogens, using diethylstilbestrol in the US and ethinylestradiol in the Netherlands by Haspels.
In the early 1970s, the Yuzpe regimen was developed by A. Albert Yuzpe in 1974; progestin-only postcoital contraception was investigated ; and the copper IUD was first studied for use as emergency contraception. 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 in many countries in the 1980s. The first prescription-only combined estrogen-progestin dedicated product, Schering PC4, was approved in the UK in January 1984 and first marketed in October 1984. Schering introduced a second prescription-only combined product, Tetragynon in Germany in 1985. By 1997, Schering AG dedicated prescription-only combined products had been approved in only 9 countries: the UK, New Zealand, South Africa, Germany, Switzerland, Denmark, Norway, Sweden and Finland ; and had been withdrawn from marketing in New Zealand in 1997 to prevent it being sold over-the-counter. Regular combined oral contraceptive pills were more commonly used for the Yuzpe regimen even in countries where dedicated products were available.
Over time, interest in progestin-only treatments increased. The Special Program on Human Reproduction, an international organization whose members include the World Bank and World Health Organization, "played a pioneering role in emergency contraception" by "confirming the effectiveness of levonorgestrel." After the WHO conducted a large trial comparing Yuzpe and levonorgestrel in 1998, combined estrogen-progestin products were gradually withdrawn from some markets in favor of progestin-only EC, although prescription-only dedicated Yuzpe regimen products are still available in some countries.
In 2002, China became the first country in which mifepristone was registered for use as EC.

Calculating effectiveness

Early studies of emergency contraceptives did not attempt to calculate a failure rate; they simply reported the number of women who became pregnant after using an emergency contraceptive. Since 1980, clinical trials of emergency contraception have first calculated probable pregnancies in the study group if no treatment were given. The effectiveness is calculated by dividing observed pregnancies by the estimated number of pregnancies without treatment.
Placebo-controlled trials that could give a precise measure of the pregnancy rate without treatment would be unethical, so the effectiveness percentage is based on estimated pregnancy rates. These are currently estimated using variants of the calendar method.
Women with irregular cycles for any reason must be excluded from such calculations. Even for women included in the calculation, the limitations of calendar methods of fertility determination have long been recognized. In their February 2014 emergency review article, Trussell and Raymond note:
Calculation of effectiveness, and particularly the denominator of the fraction, involves many assumptions that are difficult to validate...The risk of pregnancy for women requesting ECPs appears to be lower than assumed in the estimates of ECP efficacy, which are consequently likely to be overestimates. Yet, precise estimates of efficacy may not be highly relevant to many women who have had unprotected intercourse, since ECPs are often the only available treatment.

In 1999, hormonal assay was suggested as a more accurate method of estimating fertility for EC studies.

United States


United States

After the Roe v. Wade and Doe v. Bolton cases by U.S Supreme Court's 1973 ruling on abortions nationwide, governments such as federal and state have laws that allow medical professionals and institutes to deny services that pertain to reproductive health without being penalized on financial, professional or legal consequences. The Roe v. Wade case caused a historical survey to be conducted and concluded the “right to privacy” act allowing woman to have parental control over childrearing and the use of contraception for reproductive autonomy. After this woman started to become more informed about contraceptive and requesting them more often than before causing the disruption between pharmacist releasing these medications.
Within the 50 states, almost each one has constructed policies on sterilization, contraceptives and abortion services. In the late 1990s, with the rights being granted from specific policies, dispensing emergency contraceptives on issues of religious and moral objections of providing care has extended from doctors, nurses and hospitals to pharmacist and pharmacies. Furthermore, many states have insurance policies that cover contraceptives if covering other prescription drugs but have an exemption for employers or insurers on religious grounds. Since the late 1990s, broadening access to emergency contraceptives have taken different routes by many state legislatures. In some states where woman have been sexual assaulted, it is mandated to provide them with EC, other states have allowed woman to access EC without a prescription from a physician, another state has limited the ability from pharmacist to deny EC on religious or moral grounds, and in other states it discourages pharmacists from denying to fill contraceptive prescriptions in one states going as far in requiring all pharmacies to stock and fill every method of contraceptives. Nonetheless, other states have pursued the ability to restrict access of EC from state Medicaid family planning eligibility expansions or contraceptive coverage mandates, or by allowing the refusal of providing contraceptive services by pharmacist and some pharmacies.
Under federal law, a provision of the Affordable Care Act of 2010 guarantee coverage of contraceptives apply to most private health plans nationwide. It also specifically required coverage for 18 methods of contraception used by women, related counseling and services, and requires the coverage provided not to be an out-of-pocket cost to the people. Though in October 2017, the Trump administration made it easier for employers that offer health care plans to exclude contraceptive coverage. The two regulations that allow employers to reject contraceptive coverage are religious and moral objection, but the courts have blocked the enforcement of these regulations. As of today, 29 states requires that if insurers cover prescription drugs it has to provide FDA- approved prescription contraceptive drugs and devices, 14 states prohibits cost sharing for contraceptives, 10 states prohibit the restriction and delay by insurers or medical management techniques to access contraceptives, eight states do not permit the refusal by any employers or insurers but 21 states do allow the refusal to comply with the contraceptive coverage mandate.
Emergency contraceptives are the most common prescription drug denied on religious or moral belief, there have been cases where hormones, drugs and devices used to treat human immunodeficiency virus and diabetic medication have been denied. This topic continues to be fought upon on different levels, the Stormans, Inc v Wiesman case in 2016 is an example of a pharmacy and two pharmacist who held religious objections to EC. They were challenging Washington state regulations on providing all lawfully prescribed pharmaceuticals. Courts have been warned by many professional that if pharmacists are allowed to deny EC prescription on religious or moral belief it can affect public health in many accounts, and could set dangers with respect to “critical, life-saving preventive care”. The court denied the claim stating that all pharmacies even if the owner have religious objection must provide all medication and in this case EC. The pharmacy owner tried to appeal it with the Supreme Court, but was denied leaving the lower court ruling in place. Not many cases go like this, Wal-Mart which is the third largest pharmacy chain refuses to carry EC since 1997, which causes any issue for woman that live in rural areas that may not have another alternative pharmacy nearby.