Clinical trial with levo-norgestrel and testosterone oenanthate for male fertility control.

Two groups of six men took levo-norgestrel (250 or 500 microgram daily) by mouth and testosterone oenanthate (200 mg monthly, intramuscurlarly) for six months. A three months placebo period preceded the medication which was followed by a recovery phase of 6-10 months. Two volunteers withdrew due to side effects. The five men taking the low doses of levo-norgestrel (250 microgram) exhibited a reduction in sperm count, but not to azoospermia. The high dose of levo-norgestrel (500 microgram) was more effective, sperm count was reduced to < 6 X 10(6)/ml in 3 of 5 volunteers and to < 17 X 10(6)/ml in the remainder. s-Testosterone, LH and FSH were decreased by the treatment. The men had no toxicological side effects or changes in libido and potency. During the recovery period sperm counts, sperm morphology, s-testosterone, LH and FSH returned to normal levels.