How Much Do You Know About Contraception?

Other methods that require a prescription include the vaginal ring, intrauterine device (IUD), Implanon (contraceptive implant), and injectable forms of contraception. Male and female condoms and spermicides don't need a prescription.

Except for abstinence, latex condoms provide the best protection against sexually transmitted diseases (STDs) such as AIDS and herpes. One drawback to condoms is that in some people, they may cause irritation or an allergic reaction (to the latex). Condoms are available over the counter and are used once, then thrown away.

The diaphragm, available by prescription, prevents sperm from entering the uterus. It is put in place before having sex and left in place for at least six hours afterward. It is used with a spermicide designed for diaphragms. It is less effective for women who have had a vaginal birth, the FDA says, because childbirth stretches the cervix and vagina, making it more difficult to achieve and maintain a proper fit.

Two types of IUDs are available in the United States: hormonal and copper. An IUD must be put in place by a health care provider, but once that's done, the copper IUD can remain in place and is effective for up to 10 years. The hormonal IUD must be replaced every five years. The hormonal IUD may help decrease menstrual pain and bleeding. Although the IUD is convenient, it offers no protection against STDs and may contribute to pelvic inflammatory disease and infertility. The IUD usually is not recommended for women who have not had a child.

Other common side effects are headache, breast tenderness, irregular bleeding, and depression. Side effects usually decrease with time, as your body adjusts to the hormones. Oral contraceptives must be taken every day to be effective. They provide the hormones estrogen and progestin, hormones similar to those that a woman's body produces naturally. The hormones prevent ovulation and make the womb less receptive to pregnancy. Oral contraceptives offer no protection against STDs. Hormones also can be injected to provide contraception, implanted in the skin, or placed on the skin with a special patch. Hormone injections are given every three months; the implant provides contraception for three years; and the skin patch is replaced every week. Low-dose contraceptives now available have fewer side effects than do earlier versions, the FDA says. Women older than 35 who smoke and women with certain medical conditions, such as a history of blood clots, breast cancer, or endometrial cancer, should talk to their health care provider before taking oral contraceptives. These forms of contraception may increase the risk for heart disease, high blood pressure, and blood clots.

The vaginal ring is a flexible, plastic ring that is placed in the upper vagina. The ring provides the same hormones that are in oral contraceptives; in this case, they are absorbed through the lining of the vagina. The ring remains in place for 21 days; it is then removed for 7 days to allow for menstruation, and then a new one is put in place. Like other hormonal methods of contraception, it offers no protection against STDs.

Natural family planning, also called fertility awareness, involves tracking body functions as they change through a woman's menstrual cycle. Because a sperm may live in a woman's reproductive tract for up to seven days and the egg may remain fertile for about 24 hours, a woman could become pregnant from intercourse that occurred seven days earlier or 24 hours afterward, the FDA says. Natural family planning uses the menstrual cycle, changes in cervical mucus or changes in body temperature to figure out when a woman is fertile. On days when a woman is fertile, she and her partner abstain from sexual intercourse to prevent pregnancy. These methods are effective if used consistently and correctly, experts say. If used "perfectly," the basal temperature method, for example, still will result in only 2 pregnancies out of 100 women. With a typical use of this method, as many as 20 women in 100 will become pregnant. Your health care provider can supply you with more information on natural family planning.

Sterilization is a surgical procedure that blocks the pathway of the egg or sperm, the College says. In women, the fallopian tubes are cut, tied, burned, or clipped; any of these methods prevents the eggs from traveling from the ovaries to the uterus. In men, the vas deferens is cut so that sperm cannot mix with semen. Both methods are permanent forms of contraception. Reversing a tubal sterilization or vasectomy is difficult, expensive and often unsuccessful, says the National Institute of Child Health and Human Development.