The human sperm-hamster egg penetration assay: prognostic value.

Males from 227 infertile couples were evaluated using the human sperm-hamster egg penetration assay (SPA). Indications for the SPA were abnormal semen analyses, poor postcoital tests, documented autologous sperm antibodies, and long-term unexplained infertility. Normal results defined as greater than or equal to 11% penetration were seen in 58.6% of couples. Penetration rates of 1% to 10% were observed in 25.6%, and 15.9% failed to penetrate any of the oocytes. During the follow-up period, with a mean of 17.9 months, 26.9% conceived at least once with or without treatment. Monthly fecundity was 0.014 for normal SPA patients and 0.007 for the abnormal SPA group when calculated by the Kaplan-Meier survival curve with Cox correction for unequal follow-up. The monthly fecundity rate at any time during the 30-month interval of follow-up was twice as great for men with normal SPA values as for those with abnormal values, regardless of male or female diagnosis or therapy indicating the prognostic value of the SPA in an infertile population.