PREDICTING THE FERTILIZING POTENTIAL OF HUMAN SPERM SUSPENSIONS IN-VITRO - IMPORTANCE OF SPERM MORPHOLOGY AND LEUKOCYTE CONTAMINATION

Objective: To determine the relationships between sperm function tests and fertilization of human oocytes in vitro. Design: Analysis of infe rtile patients undergoing IVF therapy. Setting: Diagnostic Andrology L aboratory and Assisted Conception Service. Patients: Forty-one couples who underwent IVF-ET therapy were studied. Interventions: None Main O utcome Measures: The ability of human spermatozoa to achieve fertiliza tion in vitro was examined in relation to numerous criteria of semen q uality, including the conventional semen profile, the computer-aided a ssessment of sperm movement, ionophore-induced acrosome reaction, acri dine orange staining, sperm morphology, and chemiluminescent signals i nduced by phorbol ester and N-formyl-methionyl-leucyl-phenylalanine (F MLP). Results: Significant correlations were observed between fertiliz ation rates and several attributes of the sperm preparations, includin g elements of sperm function (acrosome reaction), movement (percentage motile, hyperactivation, the amplitude of lateral sperm head displace ment), morphology (normal morphology, midpiece defects, multiple anoma lies index), nuclear normality (acridine orange staining), and reactiv e oxygen species generation (chemiluminescence induced by phorbol este r and FMLP). In a stepwise multiple regression analysis, an accurate p rediction of fertilization rates was obtained using a multiple regress ion equation incorporating six variables of which sperm morphology and FMLP-induced chemiluminescence were the most informative. Conclusions : A set of criteria have been identified that accurately predict the f ertilizing potential of human sperm suspensions in vitro and that plac e particular emphasis on sperm morphology and the degree of leukocyte contamination.