External validation of the endometriosis fertility index (EFI) for predicting spontaneous pregnancy after surgery: further considerations on its validity.

BACKGROUND/AIMS: The revised American Society for Reproductive Medicine classification of endometriosis has a limited predictive value for pregnancy after surgery. A tool for predicting spontaneous pregnancy or pregnancy following assisted reproduction technology (ART) represents a clinical need. This study aimed to (i) provide an external validation of the EFI score in predicting pregnancy in infertile Italian endometriosis women; (ii) evaluate the predictive value of EFI score on ART outcome for patients who previously attempted to spontaneously conceive after surgery.

METHODS

In 104 women with endometriosis, EFI score was calculated based on a prospective database data. Cumulative pregnancy rates curves were calculated using Kaplan-Meier (K-M) product limit estimate and log-rank test was used to evaluate differences between EFI groups. A receiver operating characteristic (ROC) curve was plotted for EFI as a predictor of ART outcome.

RESULTS

Differences in time to non-ART pregnancy for the six EFI groups were statistically significant (log-rank, p = 1.4 × 10(-4)). The area under the curve (AUC) for EFI as ART outcome predictor was 0.75 (95% CI 0.61-0.89, p = 6.2 × 10(-3)), while the best cut-point for pregnancy was 5.5.

CONCLUSION

The EFI score is a reliable scoring system to predict non-ART and ART pregnancy outcome after surgery for endometriosis.