EMERGENCY CONTRACEPTION

Emergency contraception is used to prevent pregnancy after unprotected sex.

Forms of emergency contraception 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 medical abortion methods that act after implantation.

* Intrauterine devices (IUDs) — usually used as a primary contraception method, but sometimes used as an emergency contraceptive.

As its name implies, emergency contraception is intended for occasional use, when primary means of contraception fail.

Since emergency contraception methods act before implantation, they are medically and legally considered forms of contraception.

ECPs

Emergency contraceptive pills may contain higher doses of the same hormones (oestrogens, progestins, or both) 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 is considered an anti-hormonal drug, and does not contain oestrogen 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 under many names worldwide, including: in the US, Canada and Honduras as Plan B; in the UK, Ireland, Australia, New Zealand, Portugal and Italy as Levonelle; in 44 nations including France, most of Western Europe, India, and several countries in Africa, Asia and Latin America as NorLevo; and in 44 nations including most of Eastern Europe, Mexico and many other Latin American countries, Portugal, Australia and New Zealand, Israel, China, Hong Kong, Taiwan and Singapore as Postinor-2.

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

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 emergency contraception. As EC, 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. Mifepristone, however, is not approved for emergency contraceptive use in the United States. 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 its 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 current FDA-approved US product labelling states that levonorgestrel treatment can prevent 89% of expected pregnancies, and that EC (including the Yuzpe method) reduces the risk of pregnancy by at least 75%.

The effectiveness of emergency contraception is expressed as a percentage reduction in pregnancy rate for a single use of EC.

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) after intercourse. However, many doctors (particularly in the UK) advise use of an IUD rather than ECP's for emergency contraception between 72 and 120 hours.

ECPs as ongoing contraception

One brand of levonorgestrel pills, Postinor, is marketed as an ongoing method of postcoital contraception. However, there are serious drawbacks to such use of emergency contraception:

* Due to the increasing severity of side effects with frequent use, Postinor is only recommended for women who have intercourse four or fewer times per month.

* Used according to package directions (up to 72 hours after intercourse), levonorgestrel emergency contraceptive pills are estimated to have a perfect-use pregnancy rate of 20% per year when used as the sole means of contraception (as compared to a 40% annual pregnancy rate for the Yuzpe regimen). These failure rate are higher than those of almost all other birth control methods, including the rhythm method and withdrawal.

* Like all hormonal methods, emergency contraceptive pills do not protect against sexually transmitted infections.

ECPs are generally recommended for backup or "emergency" use, rather than as the primary means of contraception. They are intended for use 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.

Safety

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 WHO Medical Eligibility Criteria for Contraceptive Use list no medical condition for which the risks of emergency contraceptive pills (using progestin-only or combined oral contraceptive pills) outweigh the benefits, specifically noting breastfeeding and history of ectopic pregnancy as conditions where there are no restrictions on use of ECPs, and history of severe cardiovascular disease (heart attack, stroke, blood clots), angina, migraine, and severe liver disease (including jaundice) as conditions where the advantages of using emergency contraceptive pills generally outweigh the theoretical or proven risks. The American Academy of Pediatrics (AAP) and experts on emergency contraception say progestin-only ECPs may be preferable to combined ECPs containing estrogen in women with a history of blood clots, stroke, or migraine.

The AAP, American College of Obstetricians and Gynecologists (ACOG), U.S Food and Drug Administration, the WHO, the Royal College of Obstetricians and Gynaecologists's Faculty of Family Planning & Reproductive Health Care (FFPRHC) and other experts on emergency contraception state that there are no medical conditions in which progestin-only ECPs are contraindicated. The FFPRHC UK Medical Eligibility Criteria for Contraceptive Use specifically note current venous thromboembolism, current or past history of breast cancer, inflammatory bowel disease, and acute intermittent porphyria as conditions where the advantages of using emergency contraceptive pills generally outweigh the theoretical or proven risks.

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.

The AAP, ACOG, FDA, WHO, FFPRHC and experts on emergency contraception say that ECPs, like all other contraceptives, reduce the absolute risk of ectopic pregnancy by preventing pregnancies, and that the best available evidence, obtained from over 7,800 women in randomized controlled trials, indicates there is no increase in the relative risk of ectopic pregnancy in women who become pregnant after using progestin-only ECPs.

Side effects

The most common side effect of emergency contraceptive pills is nausea (50% of users of combined pills, 23% of progestin-only users), and a significant number of users vomit. Estrogen in combined ECPs is responsible for the increased incidence of nausea and vomiting. Antiemetics may be prescribed for both methods, to be taken 1 hour before each ECP dose. If vomiting occurs within an hour after taking ECP's, it may be necessary to repeat the dose.

Other common side effects are abdominal pain, fatigue, headache, dizziness, and breast tenderness. These side effects normally resolve within 24 hours.

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.

Confirmation of results

A pregnancy test is the only reliable way to confirm that EC has been effective. EC can cause menstrual changes that are similar to early signs of pregnancy, and some doctors therefore advise all women who take EC to take a pregnancy test afterwards to confirm results.[verification needed]

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. Thus, 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).

Intrauterine device

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 with normal IUD use.

IUDs may be left in place following the subsequent menstruation to provide ongoing contraception (3-10 years depending upon type).

Source: wikipedia GFDL