Your complete online medical source

Navigate by theme:


Return to index

Sexual Health

Birth Control

Birth control can help prevent unplanned pregnancies. However, no birth control method (except abstinence) is 100 percent effective and without risks. The text that follows and the chart on See Birth Control briefly describe the most common birth control methods.

Review each of the birth control methods presented in this chapter with your partner before deciding which one meets your needs. Your health professional can help you better understand the effectiveness and risks of each method.

Use all birth control methods exactly as your doctor or the package instructions recommend. Proper use helps ensure effectiveness.

Hormonal methods of birth control for women either prevent the ovaries from releasing an egg each month (ovulation) or thicken the mucus at the opening of the uterus so sperm can't get to the uterus to fertilize an egg. All hormonal birth control methods require a doctor's prescription. Hormonal methods of birth control do not protect against STDs.

Oral contraceptives (the Pill) are taken daily. Norplant is a set of small plastic cylinders that are inserted under the skin in the upper arm. The cylinders release hormones continuously for up to 5 years and can be removed whenever you decide you want to get pregnant. Depo-Provera is a hormone injection given by a health professional once every 3 months.

Birth Control





Tubal ligation (women)

Vasectomy (men)

Fewer than 1

Consider it permanent.

Hormonal Methods

Oral contraceptives (the Pill)


Increased risk of circulatory disorders and high blood pressure in women who smoke.

Norplant (implant)

Depo-Provera (shot)

Fewer than 1

Fewer than 1

Both Norplant and Depo-Provera may cause irregular menstrual bleeding.

Emergency contraception ("Morning after" pill)


May cause nausea and vomiting.

Intrauterine Device (IUD)

Fewer than 1 to 2 depending on type of IUD used

May cause bleeding and cramping. May be expelled without being noticed. Increased risk of pelvic infection.

Barrier Methods

Condom (male)


For maximum protection against STDs, use latex or polyurethane condoms every time you have sex.

Condom (female)


Diaphragm (with spermicide)


Cervical cap (with spermicide)

20 to 40


Jelly, cream, foam, suppositories


Use with a condom for best protection.

Used with condom


Periodic Abstinence


(natural family planning: basal body temperature, mucus, or rhythm/calendar method)



No method (chance)


*Typical number of accidental pregnancies per 100 women in 1 year. When birth control methods are used exactly as directed, pregnancy rates are lower. Adapted from: R. Hatcher et al., Contraceptive Technology, 1998.

The intrauterine device (IUD) is a plastic or metal device that is inserted into the uterus by a doctor. Some IUDs release a hormone to prevent conception. Other IUDs release copper, which appears to kill sperm. IUDs do not provide any protection against STDs.

"Morning after" pills can be used for emergency contraception within 72 hours of having unprotected sex. This may be an option if you had unplanned sex and did not use birth control, a condom broke or came off, you forgot 2 or more birth control pills, or you were forced to have sex. It is best to take "morning after" pills as soon as possible after having unprotected sex, because that is when they are most likely to be effective in preventing pregnancy. "Morning after" pills are available through your doctor's office, walk-in clinics, or public health units.

Barrier methods of birth control kill sperm and/or keep sperm from entering the uterus and reaching the egg. Barrier methods work best when 2 methods are combined; for example, male condoms used with spermicidal foam.

The male condom is a thin, flexible tube of latex rubber or animal skin that is placed over the man's erect penis before sexual intercourse to catch ejaculated semen. There are also condoms for women that fit inside the vagina to protect against STDs and unplanned pregnancy. Latex or polyurethane condoms provide the most reliable, but not total, protection against STDs, including HIV. Lambskin condoms are not effective in preventing STDs. Condoms are available without a doctor's prescription. Many condoms are lubricated with a spermicide. Condoms can be used with other birth control methods for added protection against STDs.

Spermicides are foams, jellies, and suppositories that contain chemicals which kill sperm. Spermicides are available without a doctor's prescription. Most spermicides contain nonoxynol-9. Some people are allergic to nonoxynol-9 and may develop sores in the vagina or on the penis after coming in contact with it. Sometimes the allergic reaction is triggered by other chemicals in the spermicide, and switching to a different product solves the problem.

The diaphragm and cervical cap are small rubber caps that are filled with spermicide and inserted into the vagina to cover the opening to the uterus (cervix) before sexual intercourse begins. They are left in place for 6 hours or longer after sexual intercourse. Both the diaphragm and the cervical cap require a doctor's prescription. When used alone, these barrier methods provide minimal protection against STDs.

Surgical methods are the most effective forms of birth control. During a vasectomy, the tubes (vas deferens) that carry a man's sperm from his testes are clamped or cut off, thus preventing sperm from being ejaculated in semen. Tubal ligation procedures close off or cut the tubes (fallopian tubes) that carry a woman's eggs from her ovaries to her uterus. This prevents eggs from being fertilized or implanting in the uterus. Both vasectomy and tubal ligation should be considered permanent, but in some cases they can be successfully reversed with surgery. Surgical methods of birth control do not protect you against STDs.

Natural family planning (fertility awareness) methods help a couple estimate when the woman is most likely to become pregnant (during ovulation) so they can avoid sexual intercourse during that time. To estimate when ovulation occurs, a woman records her temperature, examines her vaginal mucus discharge, and tracks her menstrual periods. Natural family planning is the least effective method of birth control. It does not provide protection against STDs.

Top of Page