Contraception is prevention of ovulation (stopping the ovaries from releasing eggs) or prevention of fertilization of an egg by a sperm (conception) or prevention of attachment of a fertilized egg to the lining of the uterus (implantation).
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Contraception (birth control) is used to prevent pregnancy. Contraceptive methods may be temporary (for example, birth control pills or an intrauterine device) or permanent (intended to avoid pregnancy permanently—for example, vasectomy or tubal sterilization). If unprotected sex occurs, emergency contraception may help prevent an unintended pregnancy. Emergency contraception should not be used as a routine form of contraception. Abortion is a procedure that interrupts a pregnancy and may be used to end an unintended pregnancy or when issues occur during the pregnancy.
There are many methods of contraception. None is completely effective, but some methods are far more reliable than others. Effectiveness often depends on which method is used and how closely people follow instructions. Thus, the effectiveness of a birth control method can be described in two ways:
How well it prevents pregnancy when used by most people (typical use)
How well it prevents pregnancy when instructions for use are followed exactly (perfect use)
For example, oral contraceptives (birth control pills) are very effective if a person takes them every day (perfect use). However, forgetting to take a few pills (typical use) decreases the effectiveness. In contrast, intrauterine devices (IUDs), once inserted, require nothing more until they need to be replaced. Thus, typical use is usually the same as perfect use. People tend to follow instructions more closely as they get used to a method. As a result, the difference between effectiveness with perfect use and with typical use often decreases as time passes.
Age and fertility status are factors. For a couple with normal fertility who is trying to conceive, the pregnancy rate is about 85% after 1 year if no contraceptive method is used. As women age, fertility declines. In addition, sometimes medications interact with contraceptive methods and may decrease effectiveness. For example, the antibiotic rifampin can decrease effectiveness of hormonal contraceptives (with the exception of the Age and fertility status are factors. For a couple with normal fertility who is trying to conceive, the pregnancy rate is about 85% after 1 year if no contraceptive method is used. As women age, fertility declines. In addition, sometimes medications interact with contraceptive methods and may decrease effectiveness. For example, the antibiotic rifampin can decrease effectiveness of hormonal contraceptives (with the exception of thelevonorgestrel-releasing intrauterine device).
How Effective Is Contraception?
Method | Percentage of Women Who Become Pregnant During the First Year of Perfect Use* | Percentage of Women Who Become Pregnant During the First Year of Typical Use* |
|---|---|---|
Hormonal methods (with estrogen and/or a progestin) | ||
Oral contraceptives (OCs), pills may contain two hormones (estrogen and progestin) or one hormone (progestin only) | 0.3% | 9% |
0.3% | 9% | |
0.3% | 9% | |
Progestin injection (depot medroxyprogesterone acetate)(depot medroxyprogesterone acetate) | 0.2% | 6% |
Contraceptive implant inserted under the skin | 0.05% | Same as perfect use |
0.2–0.6%, depending on the type used | Same as perfect use | |
Barrier contraceptives | ||
2% with external (male) condoms 5% with internal (female) condoms | 18% with external (male) condoms 21% with internal (female) condoms | |
Diaphragm with spermicide | 6% | 12% |
Cervical cap with spermicide | 10–13% | 8% (higher among women who have had children) |
Contraceptive gel | 7% | 14% |
Contraceptive sponge (which releases spermicide continuously) | 9% for women who have not had children 20% for women who have had children | 12% for women who have not had children 24% for women who have had children |
Spermicide alone | 18% | 28% |
Other methods | ||
Copper IUD | 0.6% | Same as perfect use |
4% or higher, depending on the method | 24% | |
Withdrawal method (coitus interruptus) | 4% | 22% |
* Age and fertility status are factors. For couples with normal fertility who are trying to conceive, the pregnancy rate is about 85% after 1 year if no contraceptive method is used. As women age, fertility declines. | ||
Besides its degree of effectiveness, each contraceptive method has other advantages and disadvantages. Choice of method depends on preferences, degree of reliability needed, and medical considerations.
Despite the higher pregnancy rate associated with condom use compared to other methods, condoms (primarily latex and synthetic condoms) provide protection against all common sexually transmitted infections (STIs), including human immunodeficiency virus (HIV) infection. As part of safer sex practices, condoms should be used even when another birth control method is also being used.
Comparing Contraceptive Methods
Method | Convenience | Side Effects | Other Considerations |
|---|---|---|---|
Hormonal methods | |||
Contraceptive implant under the skin | Implants require action only once every 3 and possibly up to 5 years. A practitioner inserts a small rod that contains a progestin under the skin of the inner arm. | Irregular or no menstrual periods during the first year Headaches and weight gain | Restrictions for use are generally less than those for contraceptives that contain estrogen. An incision is required to remove implants. |
Progestin injection (for example, depot medroxyprogesterone acetate)(for example, depot medroxyprogesterone acetate) | An injection is given by a health care professional every 12 weeks. | Irregular bleeding (more or less frequent menstrual periods), which becomes less frequent with time After 2 years, often no menstrual periods while injections are being used Weight gain, headache, mood changes, and a temporary decrease in bone density | This method reduces the risk of uterine (endometrial) cancer, pelvic inflammatory disease, and iron deficiency anemia. |
The levonorgestrel-releasing IUD requires action only once every 3, 5, or 8 years, depending on the type used.The levonorgestrel-releasing IUD requires action only once every 3, 5, or 8 years, depending on the type used. IUDs are inserted and removed by a clinician. | Irregular bleeding and/or no menstrual period | Rarely, the IUD is expelled, moves, or is perforates the uterus | |
Daily action is usually required. With estrogen-progestin oral contraceptives, a woman typically takes the contraceptive every day for 3 weeks, followed by an inactive pill every day for 1 week. Progestin-only oral contraceptives are taken every day at the same time of day. A visit to the clinician may be required periodically to have the prescription renewed. | Estrogen-progestin oral contraceptives: Breakthrough bleeding* (usually only during the first few months of use) Nausea, bloating, fluid retention, increased blood pressure, breast tenderness, headaches, and weight gain Increased risk of blood clots Progestin-only oral contraceptives: Irregular bleeding, no periods, headaches, and weight gain | Women who are 35 years or older and who smoke should not take oral contraceptives. Certain conditions prohibit the use of oral contraceptives. Women who take oral contraceptives are less likely to have menstrual cramps, premenstrual dysphoric disorder (a severe form of premenstrual syndrome), acne, and abnormal uterine bleeding. They are also less likely to develop osteoporosis and several types of cancer (such as endometrial cancer and ovarian cancer). | |
Women apply a new patch every week for 3 weeks, then remove it and leave it off for 1 week. A visit to the provider may be required periodically to have the prescription renewed. | Similar to those of oral contraceptives Skin irritation at the application site | Restrictions are similar to those of oral contraceptives. Depending on when women start using the patch, they may need to use a backup method (such as condoms and spermicide) of birth control during the first week of use. | |
Women insert a ring once every 3 weeks, then remove it and not use it for 1 week. Or they may leave the ring in place for 4 or even 5 weeks, then remove it and replace it with a new one. A new ring is used each time. A visit to the clinician may be required periodically to have the prescription renewed. | Generally similar to those of oral contraceptives, except that irregular bleeding is typically less frequent with the ring | Restrictions are similar to those of oral contraceptives. Depending on when women start using the ring, they may need to use a backup method of birth control during the first week of use. Rings may be expelled. If they are expelled and then reinserted within 3 hours, no backup method of birth control is needed. | |
Barrier methods | |||
Women may insert a cervical cap 15 minutes to 40 hours before sexual intercourse. They must leave it in place for at least 6 hours after intercourse, but it should not stay in place for longer than 48 hours. | Allergic reactions and vaginal irritation | This method cannot be used during menstruation. | |
External (male) condoms should be applied immediately before every episode of sexual intercourse. The condom should be removed carefully to avoid spilling semen. Internal condoms (female) are inserted into the vagina, and the penis is carefully guided into the condom. Condoms are discarded after one use. Condoms are available over the counter. | Allergic reactions and skin irritation | Latex condoms are the only contraceptives that provide protection against all common sexually transmitted infections (STIs), including human immunodeficiency virus (HIV) infection. Condoms made of a synthetic material such as polyurethane, polyisoprene, or silicon rubber provide some protection, but they are thinner and more likely to tear. Condoms must be used correctly to be effective. This method requires diligence and cooperation by the sex partner. | |
Contraceptive gel | The gel must be used within 1 hour before sexual intercourse. | Burning and itching in the genital area and vagina, yeast infections, and urinary tract infections | — |
The sponge can be inserted before sexual intercourse and is effective for 24 hours. It must be left in place for at least 6 hours after intercourse. It is discarded after one use. Sponges are available over the counter. | Allergic reactions and vaginal dryness or irritation | Sponges may be difficult to remove. They must be removed after 30 hours. Sponges are less effective than diaphragms. | |
Diaphragm with a spermicidal cream or gel (which kills sperm) | A diaphragm is inserted in the vagina up to 2 hours before sexual intercourse. The diaphragm should be left in place for at least 6 to 8 hours and may be left in place for up to 24 hours. A doctor can fit a diaphragm and check the fit at least once a year and after childbirth. The SILCS diaphragm is an exception The SILCS diaphragm is a single-size contraceptive barrier device that does not require fitting by a doctor. The spermicidal cream or gel used with a diaphragm may make insertion messy. | Allergic reactions, irritation in the genital area and vagina, and urinary tract infections | After initial insertion of the diaphragm, additional cream or gel should be inserted into the vagina before each episode of intercourse. |
Spermicide alone | Must be placed in the vagina at least 10 to 30 minutes and no more than 1 hour before sexual intercourse each time | Burning, irritation, and rash in the genital area and vagina and urinary tract infections | Because efficacy is limited, spermicide is often used with other barrier methods. |
Other methods | |||
Copper IUD | Copper IUDs require action only once every 10 years. IUDs are inserted and removed by a doctor. | Bleeding and/or pain Rarely, perforation of the uterus | Occasionally, the IUD is expelled. |
Women keep track of their fertile days by one or all of the following;
| None | This method requires diligence by women and abstinence from sexual intercourse several days a month. It is less effective for women with irregular menstrual cycles. | |
Withdrawal method | Men withdraw their penis from the vagina before ejaculation. Self-control and precise timing are required. | None | This method is less effective than other methods because sperm may be released before ejaculation and because the man may not withdraw before ejaculation. |
* Breakthrough bleeding is bleeding that occurs between periods, when women are taking the active pill. | |||
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Drugs Mentioned In This Article
