PREDICTION OF THE IN-VITRO FERTILIZATION (IVF) POTENTIAL OF HUMAN SPERMATOZOA USING SPERM FUNCTION-TESTS - THE EFFECT OF THE DELAY BETWEEN TESTING AND IVF

To examine the diagnostic significance of several criteria of semen qu ality and to determine whether their prognostic value is eroded by the time interval between assessment and the attempt at in-vitro fertiliz ation (IVF) with embryo transfer, 73 couples undergoing NF and embryo transfer therapy were studied. The ability of human spermatozoa to ach ieve fertilization in vitro was examined in relation to the convention al semen profile, sperm morphology, the computer-aided assessment of s perm movement, ionophore-induced acrosome reaction, acridine orange st aining, and chemiluminescent signals induced by phorbol ester and N-fo rmyl-methionyl-leucyl-phenylalanine (FMLP). Spermatozoa were examined both in semen and after preparation on Percoll, some weeks prior to IV F. Fertilization rates were noted to be significantly correlated with elements of sperm movement characteristics, sperm morphology, and reac tive oxygen species generation. Prediction of fertilization rates in a stepwise multiple regression analysis was obtained using four variabl es: sperm morphology, FMLP-induced chemi-luminescence and sperm moveme nt characteristics (beat cross frequency and straightness) (r similar to 0.5). When multiple logistic regression analysis was used to predic t which samples would achieve fertilization rates above and below a 50 % threshold, three variables of predictive value including linearity, average path velocity and FMLP-induced chemiluminescence were selected . Combination of these variables classified the samples achieving good or poor fertilization with an overall accuracy of 83.6%. The time int erval between semen assessment and IVF had little effect on the predic tive value of these tests. In conclusion, the fertilizing ability of h uman spermatozoa is related to sperm morphology, attributes of sperm m ovement and reactive oxygen species production. The time delay between testing and IVF did not appear to affect predictive accuracy.