Use of Sperm Parameters to Predict Clinical Pregnancy with Intrauterine Insemination.

Objective: To test the hypothesis that morphology is the best predictor of clinical pregnancy (CP) when employing intrauterine insemination (IUI).

Study Design: We retrospectively reviewed a registry of 527 couples who collectively underwent 1,027 IUI cycles, testing sperm parameters and other variables with univariate and multivariate analyses for association with CP. With the literature scant regarding the impact of sperm morphology on IUI outcome, we determined semen parameter threshold values in our patient population and compared them to published reference range values. A logistic regression model was used to determine predictors of CP.

Results: Fecundity was 12.9% per cycle and fertility was 23.3% by the third attempted cycle. Morphology was the most significant parameter predicting CP with IUI. Motility was also significant when employing our new threshold values. Using receiver operator characteristic curve analysis, values 16% morphology and 69% motility were found to be the optimal threshold values for achieving CP.

Conclusion: Morphology was the best predictor of CP. When considering IUI, the best chance of clinical pregnancy occurs when both motility and morphology values are above normal thresholds.