PREDICTION OF INVITRO FERTILIZATION RATES FROM SEMEN VARIABLES

Objective: To assess the value of semen variables for predicting ferti lization rates. Design: Measures of the fresh semen and the motile spe rm fraction used for insemination were related to the fertilization ra te by multiple regression analysis. The regression model was then used to construct a two-dimensional clinical chart. Setting: University-af filiated reproductive medicine unit. Patients: The results of 294 IVF cycles were analyzed retrospectively. Selection criteria were: [1] fir st cycle of IVF; [2] tubal and/or male factor infertility; and [3] fou r or more oocytes inseminated. Interventions: None. Main Outcome Measu res: The fertilization rate was related to measured variables of the f resh semen and the motile sperm fraction used for insemination. Fertil ization rate was categorized as poor (<35%) or acceptable (greater-tha n-or-equal-to 35%). Results: Multiple regression analysis demonstrated a strong correlation between the fertilization rate and the combined indexes of percentage normal morphology and grade of motility in the f resh semen and percentage progressive motility in the motile sperm fra ction. A two-dimensional chart that expressed these relationships was constructed. Its accuracy of prediction was 77% for poor fertilization and 95% for acceptable fertilization. Conclusions: The fertilization rate is strongly correlated with percentage normal sperm morphology in the fresh semen and the percentage progressive motility in the motile sperm fraction used for insemination. The clinical chart provides a s imple but powerful tool for predicting fertilization outcome.