The progesterone-induced sperm acrosome reaction is a good option for the prediction of fertilization in vitro compared with other sperm parameters.

Progesterone (P ) is crucial for the physiological function of spermatozoa. In the study, we investigated the correlation between P -induced sperm acrosome reaction (AR) and parameters including sperm progressive motility, normal morphology and sperm DNA fragmentation (SDF), and compared the in vitro fertilization (IVF) predictive values of these indicators based on the multivariate regressions analysis and receiver operator characteristics (ROC) curve analyses. The results demonstrated a negative correlation between P -induced sperm AR and the SDF, with the correlation -9.05 (-17.25 to -0.84), p<0.05, n = 47). No relationship was found between the sperm progressive motility, normal morphology and the induced AR. The P -induced AR and SDF were both significantly correlated to the fertilization rate. ROC curve analyses indicated that P -induced AR was a better prognostic predictor for the fertilization rate compared with the SDF, with the areas under the curve 0.729 (0.580-0.849), p<0.01 and 0.637 (0.484-0.772), p=0.16 respectively. The cut-off value for P -induced AR to predict "50% fertilization rate" was 23.4% with sensitivity and specificity of 63.3% and 88.2% respectively. The overall results indicated that the assessment of P -induced AR seemed to be a more sensitive indicator for fertilization rate in vitro compared with other sperm parameters.