Improvement in the sperm penetration (hamster ova) assay (SPA) results after doxycycline treatment of infertile men.

Thirty-two men with abnormal (less than or equal to 11% penetration) Sperm Penetration (hamster ova) Assay (SPA) results were treated with doxycycline and reevaluated by SPA and seminal fluid analysis. Eighteen of the 32 infertile men with initially abnormal SPAs had normal SPAs (greater than or equal to 15% egg penetration) after treatment. None of 30 untreated infertile men with abnormal SPAs had a normal SPA on repeat testing (P less than 0.001). Improvement in SPA results was associated with a decrease in the number of leukocytes/ml in seminal fluid. Seven of the wives of the treated men conceived, while none of the wives of the untreated infertile men conceived during comparable intervals of time.