Emergency contraception is the use of certain methods to prevent pregnancy after a woman has had sex without birth control or after the method she used has failed.
There are two forms of emergency contraception available in the United States: 1) emergency contraceptive pills and 2) the copper intrauterine device (IUD).
There are three types of emergency contraceptive pills: 1) progestin-only pills, 2) combination pills, and 3) ulipristal.
Progestin-only emergency contraception pills are available as a single pill or two pills that are taken 12-24 hours apart. The pills should be started as soon as possible after having unprotected sex. Progestin-only pills can be used more than once, even within the same menstrual cycle.
Progestin-only pills are thought to prevent pregnancy mainly by preventing ovulation. They will not work if you are already pregnant and will not affect a pregnancy that has started. They are about 75% effective in preventing pregnancy. Their effectiveness decreases with time. They are most effective when taken within 72 hours (3 days) of unprotected sex. They are moderately effective when taken within 120 hours (5 days).
Birth control pills that contain estrogen and progestin are called combination pills.
Taken in higher-than-usual amounts, combination birth control pills can be used for emergency contraception. They are taken in two doses. The number of pills needed for emergency contraception is different for each brand of pill. Combination emergency contraceptive pills need to be taken as soon as possible up to 120 hours, or 5 days, after unprotected intercourse. They are thought to work by preventing ovulation.
Combination emergency contraceptive pills are not as effective in preventing pregnancy as progestin-only pills. For this reason and because of the higher risk of nausea and vomiting, progestin-only methods are preferred over combination emergency contraceptive pills.
A health care provider or pharmacist can tell you how many pills you should take for the type of birth control pills that you have. This information also is available at the web site http://www.not-2-late.com.
Ulipristal can be taken up to 120 hours (5 days) after unprotected intercourse with no decrease in effectiveness. Ulipristal is available by prescription only. Research suggests that it may prevent more pregnancies than progestin-only pills when taken as directed.
Because the effects of repeated use of ulipristal are not yet known, it should be taken only once during a menstrual cycle. It also may decrease the effectiveness of hormonal birth control methods. For this reason, a nonhormonal method, such as a condom, should be used after taking ulipristal until your next menstrual period starts.
Ulipristal and combination birth control pills are available only by prescription. Both types of progestin-only pills can be bought at a pharmacy without a prescription if you are 17 years or older and by prescription if you are younger than 17 years. You can go to http://eclocator.not-2-late.com or call the Emergency Contraception Hotline (888-NOT-2-LATE) to find a health care provider who can provide a prescription. Also, many health care providers will give an advance prescription for emergency contraception.
Nausea and vomiting may occur after taking the progestin-only and combination pills. Your next menstrual period may not occur at the expected time. You may have bleeding or spotting in the week or month after the treatment. Other possible side effects include the following:
These side effects usually go away within a few days.
Possible ulipristal side effects include headache, nausea, and abdominal pain. Your menstrual period may occur earlier or later than expected. Spotting may occur.
The progestin-only pills and the combination birth control pills are safe even for women who normally are cautioned against using hormonal birth control methods. Emergency contraception is used for a much shorter period of time than regular use of a hormonal birth control method. However, these pills should not be used as long-term birth control because frequent use of emergency contraception results in more side effects.
No other tests or procedures are needed after taking emergency contraception. However, you should see your health care provider for a pregnancy test if you have not had a period within a week of when you expect it. Progestin-only pills and combination pills do not harm a pregnancy or the health of the baby if you are already pregnant. Currently, there is little information about whether ulipristal can harm a pregnancy if you are already pregnant.
It is possible to become pregnant later in the same menstrual cycle if you have used emergency contraception pills. To prevent pregnancy, you should use a barrier contraception method, such as a condom, until your next menstrual period occurs. You also can start birth control pills, the patch, or the vaginal ring immediately after taking emergency contraception, but you need to also use a barrier method until your next menstrual period starts.
The copper IUD must be inserted within 5 days of having unprotected sex. It is about 99% effective in preventing pregnancy. A benefit is that the IUD can then be used for long-term birth control. A drawback is that it does not protect against STDs. If you are at risk of STDs, a male or female condom should be used in addition to the IUD for STD protection. Also, some women with certain medical conditions cannot use an IUD.
Estrogen: A female hormone produced in the ovaries.
Intrauterine Device (IUD): A small device that is inserted and left inside the uterus to prevent pregnancy.
Ovulation: The release of an egg from one of the ovaries.
Progestin: A synthetic form of progesterone that is similar to the hormone produced naturally by the body.
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