THURSDAY, April 27, 2006 (HealthDay News) -- Although a male hormonal contraceptive is still years away, a new study shows that its effect may be reversible within a few months of discontinuing treatment.
Currently, contraception for men is limited to condoms, vasectomy and withdrawal. For many couples these methods are not acceptable, since they are either not reliable or in the case of vasectomy, not easily reversible.
An easily reversible method "is an important requirement for any contraceptive," said study lead author Dr. Peter Y. Liu, of the Department of Andrology at Concord Hospital and ANZAC Research Institute of the University of Sydney, in Australia. Therefore, his team's findings represent "an important step in the development and widespread adoption of these methods," he said.
The report appears in the April 29 issue of The Lancet.
As the researchers explained, androgen or androgen-progestin treatment combinations in men inhibit sperm production in ways that are similar to how hormone therapy suppresses ovulation in women.
Currently, there is a large phase III male contraception study involving androgen treatment and another large, multi-center phase II study involving androgen-progestin combinations ongoing in China and Europe.
But to be sure this method is reversible, researchers looked at the results of 30 studies on male hormonal contraceptives in which sperm output was monitored every month until recovery.
"Men who use androgen-progestin male contraceptive methods can all expect that their sperm output will return back to levels consistent with normal fertility," Liu concluded. "This means that these hormonal methods are reversible."
"Male contraceptives offer choices to men," added study co-author Dr. Christina Wang, a professor of medicine at the General Clinical Research Center, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center. "It will allow men to participate in family planning decisions and share family planning responsibilities," she added.
In its study, Liu's team reviewed data on 1,549 men. The researchers found that the average time for sperm recovery was 3.4 months. Factors associated with higher rates of recovery included older age, Asian origin, shorter treatment duration, and higher sperm concentrations at baseline. Although these factors affected the speed of recovery, sperm production recovered to levels compatible with fertility in all men, Liu's group found.
These male hormonal contraceptives will most likely be given by injection or a subcutaneous implant, Liu said. In addition, research is continuing into shorter-acting male hormone contraceptives delivered by skin patch or pill, Wang said.
"We are developing possibilities for short-acting, medium-acting and long-acting male contraceptives," Wang said. "There will be pills, injections, patches and implants, just like in women."
Male hormonal contraceptive methods are on the way, Liu said.
"We now have important safety information and a roadmap for future studies of recovery. This is an important step in allowing men to share more fairly the satisfaction and burden of family planning," she said.
One expert doesn't think the study addresses some important and unanswered questions about male hormonal contraceptives, however.
"Although the summary nicely overviews the recovery of sperm production for men who go on hormonal contraception, it does not address the more difficult areas -- effectiveness, side effects, and acceptability," said Dr. Peter N. Schlegel, professor and chairman of urology and professor of reproductive medicine at Weill Medical College of Cornell University, in New York City.
For more on male contraception, visit Columbia University.