Oral Contraceptive For Men Encouraging

An experimental contraceptive method for men, designed to be taken orally like the birth control pill for women, has shown promise in a small pilot study, researchers reported Wednesday.

The method sharply suppressed the sperm counts of eight healthy men who took two pills containing two synthetic hormones twice daily for 16 weeks. There were no significant side effects, and all the men’s sperm counts rebounded to normal within three months.

The findings are encouraging, but much more research is needed before such a method might prove practical, according to the researchers who conducted the study and other scientists.

“I think it’s important, but I wouldn’t want to make it sound like it’s the cure to the population problem,” said William J. Bremner of the University of Washington and Veterans Affairs Medical Center in Seattle, who helped perform the study.

Researchers have been trying for decades to develop safe and effective alternatives to condoms and vasectomies, which are the only forms of contraception currently available to men. Daily injections of the male hormone testosterone can shut off sperm production but often produce side effects, such as acne and weight gain. So scientists have been experimenting with different formulations of various synthetic hormones.

In the new study, published in the November issue of the journal Fertility and Sterility, Bremner and colleagues at the S. Orsola Hospital in Bologna, Italy, gave the eight healthy Italian men pills containing two substances, cyproterone acetate and testosterone undecanoate.

Cyproterone, which is similar to the female hormone progesterone, blocks sperm production, primarily by suppressing the pituitary gland from releasing two other hormones that stimulate the testes to make sperm.

Because cyproterone also inhibits production of testosterone, the researchers gave the men testosterone undecanoate, a synthetic form of the male hormone, primarily to ensure their libidos were unaffected.

The sperm count of one of the men hit zero, and the counts of five men fell below 3 million, which some studies have suggested is low enough to make them infertile. The sperm counts of the two remaining men also fell, but not as low.