Norplant, widely hailed as the most revolutionar contraceptive since the birth-control pill, has been approved by the Food and Drug Administration.
America's first implantable contraceptive, Norplant works by slowly releasing a synthetic hormone into a woman's body through six thin capsules that are surgically embedded in her upper left arm during a brief office procedure.
Left in place for five years or less, the capsules have about a 99 percent success rate in preventing pregnancy, studies have shown -- making Norplant more effective than any birth-control pill or intrauterine device currently on the market and as effective as surgical sterilization.
When the nearly invisible capsules are removed, a woman's fertility is completely restored and she can become pregnant almost immediately, studies have shown.
Norplant "will be our most effective method," said Jacqueline Darroch Forrest of the Alan Guttmacher Institute, a reproductive research organization in New York.
The new contraceptive will not be widely available in the United States until February, said medical director Marc Deitch of Wyeth-Ayerst Laboratories of Radnor, Pa., Norplant's U.S. marketer.
Deitch said yesterday that Norplant's price would not be announced until then but that it "will be much less than the cost of five years" of birth-control pills, for which women pay about $20 a month.
Even so, health-care providers speculated that Norplant's predicted cost of $600 to $1,000 may discourage many women, particularly poor women, from using it.
Women also may be discouraged by Norplant's most frequent side-effect -- irregular bleeding.
The contraceptive has been used by nearly half a million women in 46 countries since clinical trials first began in Chile in 1968, and a majority of them have experienced irregular menstruation, bleeding between menstrual periods, or temporary stoppage of menstruation -- effects that tend to wear off after Norplant's first year of use.
In studies in the United States and elsewhere, some Norplant users have also complained about headaches, weight gain, depression, nervousness, nausea, acne, increased facial hair and the appearance of benign but painful ovarian cysts.
Despite those side-effects, researchers at the FDA and many health organizations worldwide have concluded that Norplant is
safe, particularly since it uses no estrogen, the hormone found in many birth-control pills that has been associated with stroke and breast cancer.
Critics at the National Women's Health Network in Washington disagree, saying that Norplant's safety cannot be determined until longer studies are conducted.
First developed in the mid-1960s by the nonprofit Population Council, Norplant uses a synthetic progesterone called levonorgestrel, which prevents pregnancy by inhibiting ovulation and by changing the thickness of cervical mucus to prevent penetration by sperm.