Norplant

• Concept: Six small rods are inserted under the skin of a woman's upper arm, and these rods release the synthetic hormone progestin that prevents pregnancy.
• Success Rate: Less than one woman in 1,000 becomes pregnant in one year.
• Positives: It protects against pregnancy for up to five years -without your having to do a thing. Plus, it starts working within 24 hours of insertion.
• Negatives: Doesn't protect against STDs including HIV; may cause irregular periods, headaches, weight gain, and acne. Some women may be able to see the rods under the skin. Plus, having the rods removed can be a hassle.
• Where to Get It: Requires a visit with a health care provider; the cost for insertion is usually about $500 to $800, while removal usually costs more because it takes more time to do. Many clinics also have sliding scale fees, meaning you pay based on what you can afford.

Rhythm Method

• Concept: You keep track of a woman's menstrual cycle and have intercourse only during the "safe" (or infertile) days.
• Success Rate: Typical use is difficult to estimate with this method, but with perfect use, about nine women out of 100 become pregnant in one year.
• Positives: It's free and there are no devices to deal with. And there are no side effects (except having to go without intercourse for several days before and after ovulation).
• Negatives: Predicting when a woman will ovulate is not easy, and sperm can live inside a woman's body for several days. You have to keep careful track of your vaginal mucus, menstrual cycle, and/or body temperature to accurately track your fertility patterns beginning several months before you start relying on this method. Because of the difficulty of using this method, there are a lot of accidental pregnancies. Also, it doesn't protect against STDs, including HIV.
• Where to Get It: You will need good instruction - a class or clinician who can work with you - and several months of charting before you begin to rely on this method.

Spermicide

• Concept: A woman inserts a spermicide - available in foams, creams, jellies, films, or suppositories - deep into the vagina before sex to kill sperm before it can reach an egg.
• Success Rate: With typical use, 26 women out of 100 will become pregnant in one year. With perfect use, six women out of 100 will become pregnant in one year.
• Positives: You can buy it at any drugstore - without a prescription; it can provide lubrication for intercourse.
• Negatives: Doesn't reliably protect against STDs, including HIV; plus, the chemicals can cause irritation or allergic reactions. Some spermicides such as nonoxynol-9 have been found to cause so much irritation to the vaginal walls that they can make the user more susceptible to STD and HIV infection. It's messy, and you need to follow directions for your product carefully - this may mean waiting after inserting spermicide before having intercourse, to allow time for it to dissolve and spread. You must insert more spermicide each time you have intercourse.
• Where to Get It: At drugstores or supermarkets. The cost is $9 to $12 for the spermicide and applicator; refills cost $4 to $8.

Tubal Ligation (female sterilization)

• Concept: In a surgical procedure, a woman's fallopian tubes are blocked or cut so that sperm and egg cannot unite.
• Success Rate: Less than one woman in 100 will become pregnant in a year.
• Positives: It's a permanent form of birth control; there are no lasting side effects.
• Negatives: Offers no protection against STDs, including HIV; if the procedure fails, there's an increased chance of tubal (ectopic) pregnancy (a dangerous situation in which a fertilized egg starts to develop in one of the fallopian tubes). Although it may be possible for the surgery to be reversed if a woman decides she wants to have another child, it's complicated, expensive, and doesn't always succeed. That's why the procedure is recommended only for women who have all the children they want, or who are absolutely sure they don't ever want to have children.
• Where to Get It: Talk to your health care provider; the cost is expensive, and depends on where you have the procedure done and how much your insurance will cover.