Emergency contraception (EC) is a
birth control
Birth control, also known as contraception, anticonception, and fertility control, is the use of methods or devices to prevent unwanted pregnancy. Birth control has been used since ancient times, but effective and safe methods of birth contr ...
measure, used after
sexual intercourse
Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal penetrat ...
to prevent
pregnancy
Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins.
Pregnancy usually occurs by sexual intercourse, but ca ...
.
There are different forms of EC. Emergency contraceptive pills (ECPs), sometimes simply referred to as emergency contraceptives (ECs), or the morning-after pill, are medications intended to disrupt or delay
ovulation
Ovulation is the release of eggs from the ovaries. In women, this event occurs when the ovarian follicles rupture and release the secondary oocyte ovarian cells. After ovulation, during the luteal phase, the egg will be available to be fertilized ...
or
fertilization
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Proce ...
, which are necessary for pregnancy.
[ p. 121:]
Intrauterine device
An intrauterine device (IUD), also known as intrauterine contraceptive device (IUCD or ICD) or coil, is a small, often T-shaped birth control device that is inserted into the uterus to prevent pregnancy. IUDs are one form of long-acting rever ...
s (IUDs)usually used as a primary contraceptive methodare sometimes used as the most effective form of emergency contraception.
However, the use of IUDs for emergency contraception is relatively rare.
Definition
Emergency contraception is a
birth control
Birth control, also known as contraception, anticonception, and fertility control, is the use of methods or devices to prevent unwanted pregnancy. Birth control has been used since ancient times, but effective and safe methods of birth contr ...
measure taken to reduce the risk of pregnancy following unprotected sexual intercourse or when other regular contraceptive measures have not worked properly or have not been used correctly.
It is intended to be used occasionally and is not the same as
medical abortion
A medical abortion, also known as medication abortion, occurs when drugs (medication) are used to bring about an abortion. Medical abortions are an alternative to surgical abortions such as vacuum aspiration or dilation and curettage. Medical ...
.
Emergency contraception is offered to women who do not wish to conceive but have had unprotected sex on any day of the menstrual cycle
The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that make pregnancy possible. The ovarian cycle controls the production and release of eggs a ...
, from day 21 after giving birth, or from day five after abortion
Abortion is the termination of a pregnancy by removal or expulsion of an embryo or fetus. An abortion that occurs without intervention is known as a miscarriage or "spontaneous abortion"; these occur in approximately 30% to 40% of pregn ...
or miscarriage
Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemical lo ...
.[ Emergency contraception measures include tablets taken by mouth or the insertion of a copper intrauterine device.]
Emergency contraception is not related to medical abortion
A medical abortion, also known as medication abortion, occurs when drugs (medication) are used to bring about an abortion. Medical abortions are an alternative to surgical abortions such as vacuum aspiration or dilation and curettage. Medical ...
, which is a drug regimen administered to terminate pregnancies into the second and even third trimester.
Emergency contraceptive pills
Emergency contraceptive pills (ECPs) are sometimes referred to as emergency hormonal contraception (EHC). They are taken after unprotected sexual intercourse or the breakage of a condom
A condom is a sheath-shaped barrier device used during sexual intercourse to reduce the probability of pregnancy or a sexually transmitted infection (STI). There are both male and female condoms. With proper use—and use at every act of in ...
.
Types
A variety of emergency contraceptive pills are available, including combined estrogen and progestin pills; progestin-only (levonorgestrel
Levonorgestrel is a hormonal medication which is used in a number of birth control methods. It is combined with an estrogen to make combination birth control pills. As an emergency birth control, sold under the brand name Plan B One-Step among ...
, LNG) pills; and antiprogestin
Antiprogestogens, or antiprogestins, also known as progesterone antagonists or progesterone blockers, are a class of drugs which prevent progestogens like progesterone from mediating their biological effects in the body. They act by blocking t ...
(ulipristal acetate
Ulipristal acetate, sold under the brand name Ella among others, is a medication used for emergency contraception (birth control) and uterine fibroids. As emergency contraception it should be used within 120 hours of vaginally penetrating inter ...
) or mifepristone
Mifepristone, also known as RU-486, is a medication typically used in combination with misoprostol to bring about a medical abortion during pregnancy and manage early miscarriage. This combination is 97% effective during the first 63 days of p ...
) pills. Progestin-only and anti-progestin pills are available as specifically packaged pills for use as emergency contraceptive pills. Emergency contraceptive pills originally contained higher doses of the same hormone
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required ...
s (estrogens, progestin
A progestogen, also referred to as a progestagen, gestagen, or gestogen, is a type of medication which produces effects similar to those of the natural product, natural female sex hormone progesterone in the body. A progestin is a ''synthetic co ...
s, or both) found in regular combined oral contraceptive pill
The combined oral contraceptive pill (COCP), often referred to as the birth control pill or colloquially as "the pill", is a type of birth control that is designed to be taken orally by women. The pill contains two important hormones: progest ...
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 The Yuzpe regimen is a method of emergency contraception that uses a combination of ethinyl estradiol and levonorgestrel. It is less effective and less commonly used than a larger dose of levonorgestrel alone, a dose of ulipristal acetate, or insert ...
") have also been shown to be effective as emergency contraceptive pills.
Progestin-only emergency contraceptive pills contain levonorgestrel, either as a single tablet (or historically, as a split dose of two tablets taken 12 hours apart), 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
Over-the-counter (OTC) drugs are medicines sold directly to a consumer without a requirement for a prescription from a healthcare professional, as opposed to prescription drugs, which may be supplied only to consumers possessing a valid prescr ...
(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.
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
Perrigo Company plc is an American Irish–registered manufacturer of private label over-the-counter pharmaceuticals, and while 70% of Perrigo's net sales are from the U.S. healthcare system, Perrigo is legally headquartered in Ireland for tax ...
are available over the counter in Europe and by prescription in over 50 countries under the brand names ''ellaOne'', ''ella'' (marketed by Watson Pharmaceuticals
Actavis Generics (formerly known as Watson Pharmaceuticals and Actavis plc, prior to the acquisition of Irish-based Allergan Inc) is a global pharmaceutical company focused on acquiring, developing, manufacturing and marketing branded pharmaceuti ...
in the United States), ''Duprisal 30'', ''Ulipristal 30'', and ''UPRIS''.
The antiprogestin mifepristone
Mifepristone, also known as RU-486, is a medication typically used in combination with misoprostol to bring about a medical abortion during pregnancy and manage early miscarriage. This combination is 97% effective during the first 63 days of p ...
(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. 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 (ethinylestradiol
Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. In the past, EE was widely used for various indications such as the treatment of menopausal symptoms, gynecological disord ...
) and progestin (levonorgestrel or norgestrel
Norgestrel, sold under the brand name Ovral among others, is a progestin medication which is used in birth control pills and in menopausal hormone therapy. It is available both in combination with an estrogen and alone. It is taken by mouth.
S ...
) 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. 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 hours apart (the Yuzpe regimen The Yuzpe regimen is a method of emergency contraception that uses a combination of ethinyl estradiol and levonorgestrel. It is less effective and less commonly used than a larger dose of levonorgestrel alone, a dose of ulipristal acetate, or insert ...
), effective up to 72 hours after intercourse.
The U.S. Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...
(FDA) approved this off-label use
Off-label use is the use of pharmaceutical drugs for an unapproved indication (medicine), indication or in an unapproved age group, dose (biochemistry), dosage, or route of administration. Both prescription drugs and over-the-counter drugs (OTCs) ...
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.
Effectiveness
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:
The progestin-only regimen (using levonorgestrel) 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 (Yuzpe) regimen concluded that the best point estimate of effectiveness was 74%. A 2003 analysis of two of the largest combined (Yuzpe) 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
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...
(WHO) suggested that reasonable effectiveness may continue for up to 120 hours (5 days) after intercourse.
For 10 mg of mifepristone taken up to 120 hours (5 days) 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 (levonorgestrel 1.5 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 kg (165 lb) and is completely ineffective for women who weigh over 80 kg (176 lb). After a review by European Medicines Agency
The European Medicines Agency (EMA) is an agency of the European Union (EU) in charge of the evaluation and supervision of medicinal products. Prior to 2004, it was known as the European Agency for the Evaluation of Medicinal Products or Euro ...
, the statement was deleted from the leaflet. The agency communicated that levonorgestrel is safe and effective method of emergency contraception, regardless of body weight.
Safety
The most common side effect reported by users of emergency contraceptive pills was nausea
Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...
14 to 23% of levonorgestrel-only users and 50.5% of Yuzpe regimen users; vomiting
Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the Human nose, nose.
Vomiting can be the result of ailments like Food-poisoning, foo ...
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). Anti-emetics
An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of opioid analgesics, general anaesthetics, and chemotherapy directed against cancer. They may be ...
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 (each reported by less than 20% of levonorgestrel-only users in both the 1998 and 2002 WHO trials) were abdominal pain
Abdominal pain, also known as a stomach ache, is a symptom
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than ...
, fatigue
Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...
, headache
Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches.
Headaches can occur as a result ...
, dizziness
Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness.
Dizziness is a common medical c ...
, and breast tenderness
Breast pain is the symptom of discomfort in either one or both breasts. Pain in both breasts is often described as ''breast tenderness'', is usually associated with the menstrual period and is not serious. Pain that involves only one part of a br ...
. 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
The corpus luteum (Latin for "yellow body"; plural corpora lutea) is a temporary endocrine structure in female ovaries involved in the production of relatively high levels of progesterone, and moderate levels of estradiol, and inhibin A. It is t ...
, thus delaying menstruation by a few days. Mifepristone, if taken before ovulation, may delay ovulation by 3–4 days (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. If a woman's menstrual period is delayed by two weeks or more, it is advised that she take a pregnancy test
A pregnancy test is used to determine whether a female is pregnant or not. The two primary methods are testing for the female pregnancy hormone (human chorionic gonadotropin (hCG)) in blood or urine using a pregnancy test kit, and scanning with ...
. (Earlier testing may not give accurate results.)
Existing pregnancy is not a contraindication
In medicine, a contraindication is a condition that serves as a reason not to take a certain medical treatment due to the harm that it would cause the patient. Contraindication is the opposite of indication, which is a reason to use a certain tre ...
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
In medicine, an indication is a valid reason to use a certain test, medication, procedure, or surgery. There can be multiple indications to use a procedure or medication. An indication can commonly be confused with the term diagnosis. A diagnosis ...
for a woman with a known or suspected pregnancy because it is not effective in women who are already pregnant.
The World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...
(WHO) lists no medical condition for which the risks of emergency contraceptive pills outweigh the benefits. The American Academy of Pediatrics
The American Academy of Pediatrics (AAP) is an American professional association of pediatricians, headquartered in Itasca, Illinois. It maintains its Department of Federal Affairs office in Washington, D.C.
Background
The Academy was founded ...
(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.
There are no medical conditions in which progestin-only ECPs are contraindicated. Current venous thromboembolism
Venous thrombosis is blockage of a vein caused by a thrombus (blood clot). A common form of venous thrombosis is deep vein thrombosis (DVT), when a blood clot forms in the deep veins. If a thrombus breaks off (embolizes) and flows to the lungs to ...
, current or history of breast cancer
Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a re ...
, inflammatory bowel disease
Inflammatory bowel disease (IBD) is a group of inflammation, inflammatory conditions of the colon (anatomy), colon and small intestine, Crohn's disease and ulcerative colitis being the principal types. Crohn's disease affects the small intestine a ...
, and acute intermittent porphyria
Acute intermittent porphyria (AIP) is a rare metabolic disorder affecting the production of heme resulting from a deficiency of the enzyme porphobilinogen deaminase. It is the most common of the acute porphyrias.
Signs and symptoms
The clinical p ...
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
Ectopic pregnancy is a complication of pregnancy in which the embryo attaches outside the uterus. Signs and symptoms classically include abdominal pain and vaginal bleeding, but fewer than 50 percent of affected women have both of these symptoms. ...
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.
Interactions
The herbal preparation of St John's wort
''Hypericum perforatum'', known as St. John's wort, is a flowering plant in the family Hypericaceae and the type species of the genus ''Hypericum''.
Possibly a hybrid between '' H. maculatum'' and '' H. attenuatum'', the species can be found a ...
and some enzyme-inducing drugs (e.g. anticonvulsant
Anticonvulsants (also known as antiepileptic drugs or recently as antiseizure drugs) are a diverse group of pharmacological agents used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of b ...
s or rifampicin
Rifampicin, also known as rifampin, is an ansamycin antibiotic used to treat several types of bacterial infections, including tuberculosis (TB), mycobacterium avium complex, ''Mycobacterium avium'' complex, leprosy, and Legionnaires’ disease. ...
) may reduce the effectiveness of ECP, and a larger dose may be required,[ p.3:] especially in women who weigh more than 165 lbs.
Intrauterine device
An effective emergency contraception measure is the copper-T intrauterine device
An intrauterine device (IUD), also known as intrauterine contraceptive device (IUCD or ICD) or coil, is a small, often T-shaped birth control device that is inserted into the uterus to prevent pregnancy. IUDs are one form of long-acting rever ...
(IUD) which is generally recommended up to 5 days after unprotected intercourse or up to 5 days after probable ovulation
Ovulation is the release of eggs from the ovaries. In women, this event occurs when the ovarian follicles rupture and release the secondary oocyte ovarian cells. After ovulation, during the luteal phase, the egg will be available to be fertilized ...
.[ Some studies have found effectiveness up to 10 days after unprotected intercourse to prevent pregnancy.][ A 2021 study found that the ]hormonal IUD
A hormonal intrauterine device (IUD), also known as a intrauterine system (IUS) with progestogen and sold under the brand name Mirena among others, is an intrauterine device that releases a progestogenic hormonal agent such as levonorgestrel int ...
was as effective at emergency contraception as the copper IUD, though it is not offered by clinicians for this purpose.
Insertion of an IUD is more effective than the use of emergency contraceptive pillspregnancy 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 (12+ years).
As regular contraception
One brand of levonorgestrel
Levonorgestrel is a hormonal medication which is used in a number of birth control methods. It is combined with an estrogen to make combination birth control pills. As an emergency birth control, sold under the brand name Plan B One-Step among ...
pills was marketed as an ongoing method of postcoital contraception. However, with typical use, failure rates are expected to be higher than with the use of other birth control methods.
Like all hormonal methods, postcoital high-dose progestin-only oral contraceptive pills do not protect against sexually transmitted infection
Sexually transmitted infections (STIs), also referred to as sexually transmitted diseases (STDs) and the older term venereal diseases, are infections that are Transmission (medicine), spread by Human sexual activity, sexual activity, especi ...
s.
ECPs are generally recommended for backup or "emergency" usefor example, if a woman has forgotten to take a birth control pill or when a condom
A condom is a sheath-shaped barrier device used during sexual intercourse to reduce the probability of pregnancy or a sexually transmitted infection (STI). There are both male and female condoms. With proper use—and use at every act of in ...
is torn during sex. However, for women 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, the availability of EC pills does not appear to decrease abortion rates at the population level.
In 2012 the American Academy of Pediatrics
The American Academy of Pediatrics (AAP) is an American professional association of pediatricians, headquartered in Itasca, Illinois. It maintains its Department of Federal Affairs office in Washington, D.C.
Background
The Academy was founded ...
(AAP) stated: "Despite multiple studies showing no increased risk behaviour 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 diethylstilbestrol (DES). Currently, the standard of care is to offer ulipristal or prompt placement of a copper IUD which is the most effective form of EC. However, adherence to these best practices varies by the emergency department. Before these EC options were available (in 1996), 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.[ p. 155: ][ p. 257:] The best available evidence is that they do not have any post-fertilization effects such as the prevention of implantation. The U.S. FDA
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...
-approved labels and European EMA-approved labels (except for HRA Pharma's ''NorLevo'') levonorgestrel emergency contraceptive pills (based on labels for regular oral contraceptive pills) say they may cause endometrial
The endometrium is the inner epithelial layer, along with its mucous membrane, of the mammalian uterus. It has a basal layer and a functional layer: the basal layer contains stem cells which regenerate the functional layer. The functional layer ...
changes that discourage implantation.
Daily use of regular oral contraceptive pills can alter the endometrium (although this has not been proven to interfere with implantation), 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
The International Federation of Gynaecology and Obstetrics, usually just FIGO ("fee'go") as the acronym of its French name Fédération Internationale de Gynécologie et d'Obstétrique, is a worldwide non-governmental organisation representing ob ...
(FIGO) issued a statement that: "review of the evidence suggests that LNG evonorgestreolECPs 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
''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid d ...
'' 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
The European Medicines Agency (EMA) is an agency of the European Union (EU) in charge of the evaluation and supervision of medicinal products. Prior to 2004, it was known as the European Agency for the Evaluation of Medicinal Products or Euro ...
(EMA) 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
Mifepristone, also known as RU-486, is a medication typically used in combination with misoprostol to bring about a medical abortion during pregnancy and manage early miscarriage. This combination is 97% effective during the first 63 days of p ...
and ulipristal acetate
Ulipristal acetate, sold under the brand name Ella among others, is a medication used for emergency contraception (birth control) and uterine fibroids. As emergency contraception it should be used within 120 hours of vaginally penetrating inter ...
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.[ Post-ovulatory early luteal phase administration of 10–100 mg of ulipristal acetate resulted in a statistically significant dose-dependent 0.6 ± 2.2 mm ''decrease'' in endometrial thickness from a baseline of 10.3 ± 2.3 mm to 9.7 ± 1.8 mm (vs. a 1.3 ± 2.3 mm ''increase'' in endometrial thickness from a baseline of 10.2 ± 3.2 mm to 11.5 ± 4.1 mm with placebo administration) which the authors hypothesized could hamper implantation.] 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 (IUDs) as emergency contraceptives is to prevent fertilization because of copper toxicity to sperm
Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, whi ...
and ova
, abbreviated as OVA and sometimes as OAV (original animation video), are Japanese animated films and series made specially for release in home video formats without prior showings on television or in theaters, though the first part of an OVA s ...
. 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.
History
In 1966, gynecologist John McLean Morris and biologist Gertrude Van Wagenen at the Yale School of Medicine
The Yale School of Medicine is the graduate medical school at Yale University, a private research university in New Haven, Connecticut. It was founded in 1810 as the Medical Institution of Yale College and formally opened in 1813.
The primary te ...
, reported the successful use of oral high-dose estrogen pills as post-coital contraceptives in women and rhesus macaque
The rhesus macaque (''Macaca mulatta''), colloquially rhesus monkey, is a species of Old World monkey. There are between six and nine recognised subspecies that are split between two groups, the Chinese-derived and the Indian-derived. Generally b ...
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
Diethylstilbestrol (DES), also known as stilbestrol or stilboestrol, is a nonsteroidal estrogen medication, which is presently rarely used. In the past, it was widely used for a variety of indications, including pregnancy support for those with a ...
(DES) in the US and ethinylestradiol in the Netherlands by Haspels.
In the early 1970s, the Yuzpe regimen was developed by A. Albert Yuzpe
Abraham Albert "Al" Yuzpe (born 1938) is a Canadian obstetrician-gynecologist known for his work on human fertility and emergency contraception.RengelMarian (2000). ''Encyclopedia of Birth Control.'' Greenwood Publishing Group, The Yuzpe regimen, ...
in 1974; progestin-only postcoital contraception was investigated (1975); and the copper IUD was first studied for use as emergency contraception (1975). Danazol
Danazol, sold as Danocrine and other brand names, is a medication used in the treatment of endometriosis, fibrocystic breast disease, hereditary angioedema and other conditions. It is taken by mouth.
The use of danazol is limited by masculini ...
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 (ethinylestradiol and norgestrel), was approved in the UK in January 1984 and first marketed in October 1984. Schering introduced a second prescription-only combined product, Tetragynon (ethinylestradiol and levonorgestrel) in Germany in 198
By 1997, Schering AG
Schering AG was a research-centered German multinational pharmaceutical company headquartered in Wedding, Berlin, which operated as an independent company from 1851 to 2006. In 2006, it was bought by Bayer AG and merged to form the Bayer subsi ...
dedicated prescription-only combined products had been approved in only 9 countries: the UK (Schering PC4), New Zealand (Schering PC4), South Africa (E-Gen-C), Germany (Tetragynon), Switzerland (Tetragynon), Denmark (Tetragynon), Norway (Tetragynon), Sweden (Tetragynon) and Finland (Neoprimavlar); and had been withdrawn from marketing in New Zealand in 1997 to prevent it being sold over-the-counte
Regular combined oral contraceptive pills (which were less expensive and more widely available) 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 (HRP), an international organization whose members include the World Bank
The World Bank is an international financial institution that provides loans and grants to the governments of low- and middle-income countries for the purpose of pursuing capital projects. The World Bank is the collective name for the Interna ...
and World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...
, "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 (''Preven'' in the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
discontinued May 2004, ''Schering PC4'' in the UK discontinued October 2001, and ''Tetragynon'' in France) 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.
In 2020, Japan announced it would consider easing regulations on the sale of emergency contraceptive pills without a prescription. Non-profit groups submitted a petition to the health ministry calling for prescription-free access to the pill. They had collected more than 100,000 signatures.
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
Calendar-based methods are various methods of estimating a woman's likelihood of fertility, based on a record of the length of previous menstrual cycles. Various methods are known as the Knaus–Ogino method and the rhythm method. The standard days ...
.
Women with irregular cycles for any reason (including recent hormone use such as oral contraceptives and breastfeeding
Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that br ...
) 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:
In 1999, hormonal assay was suggested as a more accurate method of estimating fertility for EC studies.
United States
DES
* In 1971, a ''New England Journal of Medicine
''The New England Journal of Medicine'' (''NEJM'') is a weekly medical journal published by the Massachusetts Medical Society. It is among the most prestigious peer-reviewed medical journals as well as the oldest continuously published one.
Hist ...
'' editorial calling attention to previously published studies on the use of DES
Des is a masculine given name, mostly a short form (hypocorism) of Desmond. People named Des include:
People
* Des Buckingham, English football manager
* Des Corcoran, (1928–2004), Australian politician
* Des Dillon (disambiguation), sever ...
as a postcoital contraceptive at Yale University
Yale University is a private research university in New Haven, Connecticut. Established in 1701 as the Collegiate School, it is the third-oldest institution of higher education in the United States and among the most prestigious in the wo ...
, and a large study published in ''JAMA
''The Journal of the American Medical Association'' (''JAMA'') is a peer-reviewed medical journal published 48 times a year by the American Medical Association. It publishes original research, reviews, and editorials covering all aspects of biom ...
'' on the use of DES as a postcoital contraceptive at the University of Michigan
, mottoeng = "Arts, Knowledge, Truth"
, former_names = Catholepistemiad, or University of Michigania (1817–1821)
, budget = $10.3 billion (2021)
, endowment = $17 billion (2021)As o ...
, led to off-label use of DES as a postcoital contraceptive becoming prevalent at many university health services.
* In May 1973, in an attempt to restrict off-label use of DES as a postcoital contraceptive to emergency situations such as rape
Rape is a type of sexual assault usually involving sexual intercourse or other forms of sexual penetration carried out against a person without their consent. The act may be carried out by physical force, coercion, abuse of authority, or ag ...
, a ''FDA Drug Bulletin'' was sent to all U.S. physicians and pharmacists that said the FDA had approved, under restricted conditions, postcoital contraceptive use of DES. (In February 1975, the FDA Commissioner testified that the only error in the May 1973 ''FDA Drug Bulletin'' was that the FDA had not approved postcoital contraceptive use of DES).
* In September 1973, the FDA published a proposed rule specifying patient labeling and special packaging requirements for any manufacturer seeking FDA approval to market DES as a postcoital contraceptive, inviting manufacturers to submit abbreviated new drug applications (ANDAs) for that indication, and notifying manufacturers that the FDA intended to order the withdrawal of DES 25 mg tablets (which were being used off-label as postcoital contraceptives).
* In late 1973, Eli Lilly
Eli Lilly (July 8, 1838 – June 6, 1898) was an American soldier, pharmacist, chemist, and businessman who founded the Eli Lilly and Company pharmaceutical corporation. Lilly enlisted in the Union Army during the American Civil War and r ...
, the largest U.S. manufacturer of DES, discontinued its DES 25 mg tablets and in March 1974 sent a letter to all U.S. physicians and pharmacists telling them it did not recommend use of DES as a postcoital contraceptive.
* Only one pharmaceutical company, Tablicaps, Inc., a small manufacturer of generic drug
A generic drug is a pharmaceutical drug that contains the same chemical substance as a drug that was originally protected by chemical patents. Generic drugs are allowed for sale after the patents on the original drugs expire. Because the active ch ...
s, ever submitted (in January 1974) an ANDA for use of DES as an emergency postcoital contraceptive, and the FDA never approved it.
* In February 1975, the FDA said it had not yet approved DES as a postcoital contraceptive, but would after March 8, 1975, permit marketing of DES for that indication in emergency situations such as rape or incest ''if'' a manufacturer obtained an approved ANDA that provided patient labeling and special packaging as set out in a FDA final rule published in February 1975. To discourage off-label use of DES as a postcoital contraceptive, in February 1975 the FDA ordered DES 25 mg (and higher) tablets removed from the market and ordered the labeling of lower doses (5 mg and lower) of DES still approved for other indications be changed to state: "THIS DRUG PRODUCT SHOULD NOT BE USED AS A POSTCOITAL CONTRACEPTIVE" in block capital letters on the first line of the physician prescribing information package insert and in a prominent and conspicuous location of the container and carton label.
* In March 1978, a ''FDA Drug Bulletin'' was sent to all U.S. physicians and pharmacists which said: "FDA has not yet given approval for any manufacturer to market DES as a postcoital contraceptive. The Agency, however, will approve this indication for emergency situations such as rape or incest if a manufacturer provides patient labeling and special packaging. To discourage 'morning after' use of DES without patient labeling, FDA has removed from the market the 25 mg tablets of DES, formerly used for this purpose."
* In the 1980s, off-label use of the Yuzpe regimen superseded off-label use of DES for postcoital contraception.
** DES is no longer commercially available in the U.S.; Eli Lilly, the last U.S. manufacturer, ceased production in spring 1997.
Preven
* On February 25, 1997, the FDA posted a notice in the ''Federal Register
The ''Federal Register'' (FR or sometimes Fed. Reg.) is the official journal of the federal government of the United States that contains government agency rules, proposed rules, and public notices. It is published every weekday, except on feder ...
'' saying it had concluded that the Yuzpe regimen was safe and effective for off-label use as postcoital EC, was prepared to accept NDAs for COCPs labeled as ECPs, and listed 6 then available COCPs (there are now 22) that could be used as ECPs.
* On September 1, 1998, the FDA approved the prescription Yuzpe regimen Preven Emergency Contraception Kit (which contained a urine pregnancy test and 4 COCPs). Preven was discontinued in May 2004.
Plan B
* On July 28, 1999, the FDA approved the prescription progestin-only Plan B (two 750 µg levonorgestrel
Levonorgestrel is a hormonal medication which is used in a number of birth control methods. It is combined with an estrogen to make combination birth control pills. As an emergency birth control, sold under the brand name Plan B One-Step among ...
pills) emergency contraceptive.
* On August 24, 2006, the FDA approved nonprescription behind-the-counter access to Plan B from pharmacies staffed by a licensed pharmacist for women 18 or older; a prescription-only form of Plan B was made available for younger females aged 17 and younger.
* On November 6, 2006, Barr Pharmaceuticals
Barr Pharmaceuticals was a global specialty and generic drug manufacturer with operations in 30 countries.
Approximately 75% of the company's revenues were from the sale of generic drugs, including 18% of sales which were from the sale of oral co ...
announced that its subsidiary, Duramed Pharmaceuticals, had initiated shipment of dual-label Plan B OTC/Rx and it would be available in pharmacies across the U.S. by mid-November 2006.
* On March 23, 2009, a US judge ordered the FDA to allow 17-year-olds to acquire Plan B without a prescription. This now changes the August 24, 2006, ruling and Plan B is now available "behind the counter" for men and women. There is a prescription method available for girls under 17.
* On April 30, 2013, the FDA approved (with three-year marketing exclusivity) Teva Pharmaceutical Industries
Teva Pharmaceutical Industries Ltd. (also known as Teva Pharmaceuticals) is an Israeli multinational pharmaceutical company with headquarters in Tel Aviv, Israel. It specializes primarily in generic drugs, but other business interests include ...
' Plan B One-Step for sale without a prescription to anyone age 15 or over who can show proof of age such as a driver's license
A driver's license is a legal authorization, or the official document confirming such an authorization, for a specific individual to operate one or more types of motorized vehicles—such as motorcycles, cars, trucks, or buses—on a public ...
, birth certificate
A birth certificate is a vital record that documents the birth of a person. The term "birth certificate" can refer to either the original document certifying the circumstances of the birth or to a certified copy of or representation of the ensuin ...
, or passport
A passport is an official travel document issued by a government that contains a person's identity. A person with a passport can travel to and from foreign countries more easily and access consular assistance. A passport certifies the personal ...
to a drug store retail clerk
A retail clerk, also known as a salesclerk, shop clerk, retail associate or (in the United Kingdom) shop assistant or customer service assistant, is a service role in a retail business.
A retail clerk obtains or receives merchandise, totals bil ...
.
Generic
Generic or generics may refer to:
In business
* Generic term, a common name used for a range or class of similar things not protected by trademark
* Generic brand, a brand for a product that does not have an associated brand or trademark, other ...
one-pill levonorgestrel emergency contraceptives and all two-pill levonorgestrel emergency contraceptives will remain restricted to sale from a pharmacist
A pharmacist, also known as a chemist (Commonwealth English) or a druggist (North American and, archaically, Commonwealth English), is a healthcare professional who prepares, controls and distributes medicines and provides advice and instructi ...
—without a prescription to anyone age 17 or over who can show proof of age.
* On June 10, 2013, the Obama administration ceased trying to block over-the-counter availability of the pill. With this reversal it means that any person will be able to purchase the Plan B One-Step without a prescription.
Availability
The COVID-19 pandemic in the United Kingdom
The COVID-19 pandemic in the United Kingdom is a part of the worldwide pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In the United Kingdom, it has resulted in confir ...
was reported to have caused "significant disruption" to contraceptive services in the United Kingdom.
United States
After Roe v. Wade
''Roe v. Wade'', 410 U.S. 113 (1973),. was a landmark decision of the U.S. Supreme Court in which the Court ruled that the Constitution of the United States conferred the right to have an abortion. The decision struck down many federal and st ...
and Doe v. Bolton
''Doe v. Bolton'', 410 U.S. 179 (1973), was a decision of the Supreme Court of the United States overturning the abortion law of Georgia. The Supreme Court's decision was released on January 22, 1973, the same day as the decision in the better-kno ...
resulted in the U.S. Supreme Court's 1973 ruling to legalize abortion, both Federal and State laws were created in order to allow medical professionals and institutions the right to deny reproductive health
Sexual and reproductive health (SRH) is a field of research, healthcare, and social activism that explores the health of an individual's reproductive system and sexual wellbeing during all stages of their life.
The term can also be further de ...
services without financial, professional, or legal penalty. Roe v. Wade caused a historical survey to be conducted and concluded that right to privacy
The right to privacy is an element of various legal traditions that intends to restrain governmental and private actions that threaten the privacy of individuals. Over 150 national constitutions mention the right to privacy. On 10 December 1948 ...
cases such as Griswold v. Connecticut
''Griswold v. Connecticut'', 381 U.S. 479 (1965), was a landmark decision of the U.S. Supreme Court in which the Court ruled that the Constitution of the United States protects the liberty of married couples to buy and use contraceptives withou ...
allowed women to have parental control over childrearing, including the use of contraception for reproductive autonomy. After this, women became more informed about contraceptives and began requesting them more often.
Almost all 50 states have implemented policies on sterilization, contraceptives
Birth control, also known as contraception, anticonception, and fertility control, is the use of methods or devices to prevent unwanted pregnancy. Birth control has been used since ancient times, but effective and safe methods of birth contr ...
, and abortion services. Since the late 1990s, due to rights given by specific policies, the dispensation of emergency contraceptives on issues of religious and moral objections of providing care has extended from doctors, nurses, and hospitals to pharmacies and individual pharmacists. Furthermore, many states have insurance policies that cover contraceptives alongside all other prescription drugs, but may have exemptions for employers or private insurers on religious grounds. Different state legislatures have taken different routes in broadening access to emergency contraceptives. In some states, if a woman has been sexually assaulted, it is mandatory to provide her access to EC. In other states, women have been allowed various amounts of access, including the ability to access EC without a prescription from a physician, creation of policies limiting the ability of pharmacists to deny EC on religious and moral grounds, and creation of policies discouraging pharmacists from denying to fill contraceptive prescriptions. One state even requires all pharmacies to stock and fill every method of contraception. However, other states have restricted access of emergency contraception from state Medicaid
Medicaid in the United States is a federal and state program that helps with healthcare costs for some people with limited income and resources. Medicaid also offers benefits not normally covered by Medicare, including nursing home care and pers ...
family planning eligibility expansions or contraceptive coverage mandates, or by allowing the refusal of providing contraceptive services by healthcare professionals.
Under federal law, a provision of the Affordable Care Act
The Affordable Care Act (ACA), formally known as the Patient Protection and Affordable Care Act and colloquially known as Obamacare, is a landmark U.S. federal statute enacted by the 111th United States Congress and signed into law by Presid ...
of 2010 has guaranteed coverage of contraceptives, applying to most private health plans nationwide. The provision has also specifically required coverage for 18 methods of contraception used by women, related counselling and services, and requires the coverage provided not to be an out-of-pocket cost to the people. In October 2017, however, 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 require that if insurance covers prescription drugs, it has to provide FDA-approved prescription contraceptive drugs and devices. 10 states prohibit the restriction and delay by insurers or medical management techniques to access contraceptives, and 8 states do not permit refusal on religious or moral grounds by any employers or insurerers. However, 21 states do allow the refusal to comply with the contraceptive coverage mandates, and 14 states prohibit cost sharing for contraceptives.
Emergency contraceptives are the most common prescription drug denied due to of religious or moral beliefs. There have been cases where hormones, drugs and devices used to treat human immunodeficiency virus and diabetic medication have also been denied. This topic continues to be fought upon on different levels; for example, Stormans, Inc v Wiesman challenged Washington state regulations on providing all lawfully prescribed pharmaceuticals, including EC.[https://www.supremecourt.gov/opinions/15pdf/15-862_2c8f.pdf ] They were challenging Washington state regulations on providing all lawfully prescribed pharmaceuticals. Courts have been warned that if pharmacists are allowed to deny EC prescriptions on religious or moral beliefs, it can affect public health and set a dangerous precedent with respect to "critical, life-saving preventative care". The court denied the claim, stating that all pharmacies, even if the owner has a religious objection, must provide all prescribed medication, including EC. The pharmacy in question tried to appeal the case to the Supreme Court, but the appeal was rejected, leaving the lower court's ruling in place. Wal-Mart, the third largest U.S. pharmacy chain, refused to carry EC from 1997 to 2006, which shows that accessibility may still be an issue in areas dependent on single pharmacies with no alternatives.
See also
* Rape crisis center
Rape crisis centers (RCCs) are community-based organizations affiliated with the anti-rape movement that work to help victims of rape, sexual abuse, and sexual violence. Central to a community's rape response, RCCs provide a number of services, su ...
* Reproductive Health Supplies Coalition
The Reproductive Health Supplies Coalition (RHSC) is a global partnership of public, private and non-governmental organizations. Its aim is to ensure that all people in low- and middle-income countries can choose, obtain and use the supplies and a ...
References
External links
Emergency Contraceptive Pills Medical and Service Delivery Guidance
4th edition
The Emergency Contraception Website (not-2-late.com)
by the Office of Population Research
The Office of Population Research (OPR) at Princeton University is the oldest population research center in the United States. Founded in 1936, the OPR is a leading demographic research and training center. Recent research activity has primarily f ...
at Princeton University
Princeton University is a private university, private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial Colleges, fourth-oldest ins ...
and the Association of Reproductive Health Professionals
The Association of Reproductive Health Professionals (ARHP) was a non-profit organization founded in 1963 by Alan Frank Guttmacher. It was a membership association of nurse practitioners, nurse midwives, pharmacists, physician assistants, physici ...
. Information for women who need emergency contraception now.
Planned Parenthood web site.
Educational web site with information for women who need emergency contraception now.
International Consortium for Emergency Contraception
Policy-oriented web site directed at professionals.
Emergency contraception
by the Adolescent Medicine Committee, Canadian Pediatric Society (CPS), ''Paediatrics and Child Health'' ACSA-CAAH The Canadian Association for Adolescent Health (also known in French as l'Association Canadienne pour la Santé des Adolescents) is a multidisciplinary, non-profit advocacy organization based in Montreal, Quebec which promotes interest in health iss ...
Use of Emergency Contraception Among Women Aged 15-44, United States, 2006-2010
National Center for Health Statistics
The National Center for Health Statistics (NCHS) is a U.S. government agency that provides statistical information to guide actions and policies to improve the public health of the American people. It is a unit of the Centers for Disease Control ...
{{DEFAULTSORT:Emergency Contraception
Hormonal contraception
Intrauterine contraception
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