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NATIONAL BRIEFING - BIRTH CONTROL: A MALE HORMONE INJECTION MAY BE ON HORIZON
The first large clinical study showing that regular doses of testosterone can act as a contraceptive has just been completed by the World Health Organization. The study of 357 men in nine countries found that weekly injections of testosterone enanthate, a synthetic form of the hormone, yielded just a 1.4% chance that a woman would become pregnant in a year. That statistic rivals the 3% failure rate of the Pill in its first year of use, and is a "vast improvement" over the failure rate of the condom, which fails at least 12% of the time. Harbor-UCLA and the Univ./WA in Seattle are the two U.S. centers participating in the WHO study. A report on the study is due out later this year. In the first phase of the study, completed in '90, hundreds of men were injected weekly with 200 milligrams of testosterone, and those whose sperm count fell to zero were identified. During that first phase, pregnancy rates among those men was 1%, but those results were limited because only 60-70% of men can be expected to lose all sperm production from the injections. In the second phase, the study tested whether men needed to have a zero sperm count in order to be infertile. In this phase, researchers studied men whose sperm counts fell to between three million and five million, from a normal rate of production of 20-200 million. The pregnancy rates among these men was the same as that of the Pill. This meant that the injections had "wider potential than previously believed, because 97.8% of healthy men tested reached those target sperm levels." The injections of the synthetic testosterone increase the blood level of the hormone, causing the pituitary to stop stimulating the testes to produce more testosterone, decreasing sperm production. The injections had some side effects, including acne. In addition, doctors remain concerned about the possible effect on cholesterol levels and prostate cancer (Monmaney, L.A. TIMES, 7/31). WHAT DOES IT ALL MEAN? L.A. TIMES' Monmaney notes that a new male method of birth control "would be unlikely to set off a sexual revolution, as the Pill did in the '60s, the threat of AIDS and sexually transmitted diseases having done away with carefree conjugations. Yet it probably would realign sexual relations in an era increasingly concerned about risks, rights and responsibilities." Harbor-UCLA's Dr. Ronald Swerdloff, who is involved in the study, said, "The importance of the study is that it shows that a male-directed hormonal contraceptive can be about as effective as the female-directed birth control pill." Alan Guttmacher Institute's Susheela Singh said she "would be excited if it was a safe, effective and affordable method. It's something to really go after." But she added that feminists and family planners "struggle against the underlying male resistance to sharing that responsibility." In addition, "technical and even legal hurdles must be overcome" before such a contraceptive may be sold in the U.S., and it is unclear how long that might take. Because many men would be reluctant to take shots, researchers are working on a testosterone compound that could suppress sperm production. "But the problem that most deeply troubles some scientists won't be solved in the lab. It goes to the heart of American society, some say the American character: litigiousness." The study has, however, offered evidence that men are not reluctant to share the responsibility of birth control (7/31).