HUMAN SPERM HYPERACTIVATION AND ACROSOME REACTION AND THEIR RELATIONSHIPS TO HUMAN INVITRO FERTILIZATION

Objective: To determine the relationships between human sperm hyperact ivation (HA) and acrosome reaction with fertilization of human oocytes in vitro. Design: Prospective analysis of infertile patients undergoi ng IVF. Setting: Tertiary center for infertility and assisted reproduc tive technology.Patients: Fifty-two couples who underwent IVF or GIFT were studied. The male partners had normal semen parameters on routine analyses. Interventions: None. Main Outcome Measures: Sperm HA in sem inal fluid and after 1 and 6 hours incubation in capacitation media; s perm acrosome reaction after 0, 6, and 24 hours' incubation in capacit ation media; and fertilization rate of human oocytes. Results: The per cent spermatozoa with transitional HA after 6 hours of incubation corr elated significantly with the fertilization rate of human oocytes. Mul tivariate discriminant analyses selected six sperm HA and acrosome rea ction variables of predictive value in classifying semen samples that achieved fertilization rates above and below 70% threshold. Combinatio n of the selected sperm HA and acrosome reaction variables in seminal fluid and after different times of incubation in capacitation medium c lassified the samples achieving good or poor fertilization rate with > 80% accuracy. Conclusions: Assessment of sperm HA and acrosome reactio n may be of prognostic value in prediction of human oocyte fertilizati on rates.