Relationship between Serum Gonadotropins and Spermatogenic Suppression in Men Undergoing Steroidal Contraceptive Treatment

This study aimed to establish whether the degree of suppression of serum FSH and LH was related to sperm concentration in three testosterone (T) plus progestin contraceptive regimens. We measured serum FSH and LH using a modified, highly sensitive immunofluorometric assay in samples obtained from three published studies using T enanthate (TE; 100 and 200 mg weekly) plus daily oral doses of cyproterone acetate (CPA; 5-100 mg), levonogestrel (LNG; 150-500 μg), or desogestrel (DSG; 150-300 μg). Overall, men with sperm concentrations below 0.1 million/ml had significantly lower gonadotropin levels (serum FSH, ∼0.12 IU/liter; serum LH, ∼0.05 IU/liter) than oligospermic men (sperm concentrations, 0.1-5 million/ml; serum FSH, 0.23-0.5 IU/liter; serum LH, 0.05-0.56 IU/liter), but the relationship was weak, indicating the possible existence of other determinants. Multivariate logistic regression was used to identify the influence of candidate predictors of spermatogenic effects of the T plus progestin regimens. In the LNG and DSG studies, the marked suppression of serum LH to less than 5% of baseline values (