Men given a hormone-based contraceptive, which could be available in the near future, can regain their fertility about four months after stopping the treatment, researchers said on Friday.
Drug companies have been working on a male pill or injection to inhibit sperm production and give couples a greater choice of family planning methods.
Scientists who analyzed studies involving men who had been given the contraceptives in trials found the treatments were highly effective but reversible.
“Hormonal male contraceptive methods could soon become widely available,” said Peter Liu from the Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center.
“These findings thereby increase the promise of new contraceptive drugs allowing men to share more fairly the satisfaction and burden of family planning,” he added in the report published in The Lancet medical journal.
Large-scale trials of male hormone-based contraceptives are being conducted in China and Europe, according to the scientists.
Liu and his team analyzed data on 1,500 men who had taken part in 30 trials which had been published between 1990-2005. Their sperm production had been monitored each month until their sperm count hit 20 million per mL (milliliter), which is considered fertile.
The researchers said various factors, including age, original sperm count, duration of treatment and ethnic origin, could influence the recovery rate.