Clomiphene citrate does not improve spermatozoal fertilizing capacity in idiopathic oligospermia

Clomiphene citrate (CC) was given to 24 men with idiopathic oligospermia at a daily dose of 25 mg (10 subjects) or 50 mg (14 subjects). Sperm concentration increased slightly after CC treatment in both groups. Sperm motility and morphology remained unchanged. Spermatozoal fertilizing capacity as assessed by the zona-free hamster ova penetration test showed no significant change throughout the treatment period. Two pregnancies occurred in the partners of the subjects treated with 50 mg CC/day, but none occurred in the other group. We conclude that oral administration of CC does not improve fertilizing capacity of sperm as measured by the zona-free hamster ova penetration test in idiopathic oligospermia.