Methods of hormonal contraception, when used properly, are extremely effective.

Norplant

Norplant--the first contraceptive implant-was approved by FDA in 1990. In a minor surgical procedure, six matchstick-sized rubber capsules containing progestin are placed just underneath the skin of the upper arm. The implant is effective within 24 hours and provides progestin for up to five years or until it is removed. Both the insertion and the removal must be performed by a qualified professional.

Because contraception is automatic and does not depend on the user, the failure rate for Norplant is less than 1 percent for women who weigh less than 150 pounds. Women who weigh more have a higher pregnancy rate after the first two years.

Women who cannot take birth control pills for medical reasons should not consider Norplant a contraceptive option. The potential side effects of the implant include: irregular menstrual bleeding, headaches, nervousness, depression, nausea, dizziness, skin rash, acne, change of appetite, breast tenderness, weight gain, enlargement of the ovaries or fallopian tubes, and excessive growth of body and facial hair. These side effects may subside after the first year.

Depo-Provera

Depo-Provera is an injectable form of a progestin. It was approved by FDA in 1992 for contraceptive use. Previously, it was approved for treating endometrial and renal cancers. Depo-Provera has a failure rate of only 1 percent. Each injection provides contraceptive protection for 14 weeks. It is injected every three months into a muscle in the buttocks or arm by a trained professional. The side effects are the same as those for Norplant and progestin-only pills. In addition, there may be irregular bleeding and spotting during the first months followed by periods of amenorrhea (no menstrual period). About 50 percent of the women who use Depo-Provera for one year or longer report amenorrhea. Other side effects, such as weight gain and others described for Norplant, may occur.

Intrauterine Devices

IUDs are small, plastic, flexible devices that are inserted into the uterus through the cervix by a trained clinician. Only two IUDs are presently marketed in the United States: ParaGard T380A, a T-shaped device partially covered by copper and effective for eight years; and Progestasert, which is also T-shaped but contains a progestin released over a one-year period. After that time, the IUD should be replaced. Both IUDs have a 4 to 5 percent failure rate.

It is not known exactly how IUDs work. At one time it was thought that the IUD affected the uterus so that it would be inhospitable to implantation. New evidence, however, suggests that uterine and tubal fluids are altered, particularly in the case of copper-bearing IUDs, inhibiting the transport of sperm through the cervical mucus and uterus.
 

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