Bromocriptine for idiopathic oligo/asthenospermia
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BACKGROUND: Oligo-astheno-teratospermia (sperm of low concentration, reduced motility and increased abnormal morphology)of unknown cause is common and the need for treatment is felt by patients and doctors alike. As a result, a variety of empirical, non-specific treatments have been used in an attempt to improve semen characteristics and fertility. Whilst bromocriptine treatment for reducing prolactin levels in hyperprolactinaemic males (as in females), and, in the treatment of hypogonadotropic hypogonadism with hyperprolactinaemia, is beneficial, it has also been used for oligospermic men in the absence of any endocrinopathy. Prolactin may play a direct role in spermatogenesis and hormone production. It has also been claimed that in oligospermic men with normal gonadotrophins mean prolactin levels are higher and that hyperprolactinaemia is more common compared to fertile men. It has been proposed that the administration of bromocriptine under these circumstances might counteract a prolactin-induced block on the action of gonadotrophins on the testicles and, subsequently, that the reduction in prolactin levels might lead to an improvement in semen parameters and fertility. Although it is not licensed for use in male infertility, bromocriptine has been used for normogonadotrophic individuals with oligospermia and normal or sligthly elevated prolactin levels. This review considers the available evidence of the effect of bromocriptine therapy for normoprolactinaemic males with idiopathic oligo and/or asthenospermia. OBJECTIVES: The objective of this review was to assess the effects of bromocriptine on pregnancy rates among couples where subfertility has been attributed to idiopathic oligo- and/or asthenospermia. SEARCH STRATEGY: The Cochrane Subfertility Review Group specialised register of controlled trials was searched". SELECTION CRITERIA: Randomised trials of oral bromocriptine versus placebo or no treatment for couples with subfertility attributed to male factor. DATA COLLECTION AND ANALYSIS: Data were extracted by one reviewer and any disagreements were resolved by discussion with other reviewers. MAIN RESULTS: Four studies were included. The method of randomisation was not specified in any of the trials, which were all of crossover design. Compared with placebo, bromocriptine was associated with a significant reduction in serum prolactin levels (weighted mean difference -195.3 micro international units per litre, 95% confidence interval -276.5 to -114). No effects on sperm parameters were seen. There was also no effect on pregnancy rates observed between bromocriptine and placebo (0.70 odds ratio, 95% confidence interval 0.15 to 3.24). REVIEWER'S CONCLUSIONS: Bromocriptine appears to reduce prolactin levels in subfertile men with normal gonadotrophic function. There is not enough evidence to show that bromocriptine is helpful in improving fertility.