Validation of Endometriosis Fertility Index for the Prediction of Non-Assisted Reproductive Technology (ART) Pregnancy in Women With Endometriosis-Associated Infertility: A Prospective Cohort Study.

Introduction Endometriosis is a common cause of infertility and affects reproductive outcomes through multiple mechanisms, including pelvic adhesions, altered pelvic anatomy, and inflammatory changes. The Endometriosis Fertility Index (EFI) was developed as a prognostic tool to predict spontaneous conception after the surgical treatment of endometriosis. This study aimed to validate the EFI for predicting non-assisted reproductive technology (ART) pregnancy outcomes after laparoscopic surgery in women with endometriosis-associated infertility and compare its predictive performance with the revised American Society for Reproductive Medicine (r-ASRM) classification. Methods A prospective cohort study was conducted in the Department of Obstetrics and Gynecology at All India Institute of Medical Sciences (AIIMS), New Delhi, between January 2016 and December 2017 with a six-month postoperative follow-up. Seventy-two women with endometriosis-associated infertility confirmed during operative laparoscopy were included. EFI scores were calculated postoperatively using historical parameters (age, the duration of infertility, and prior pregnancy) and surgical parameters (Least Function Score {LFS} and ASRM score). Patients underwent individualized fertility management, including expectant management, ovulation induction, and intrauterine insemination (IUI) where indicated. Receiver operating characteristic (ROC) analysis, Kaplan-Meier survival analysis, and Cox proportional hazards regression were performed to assess predictive accuracy. Results The mean EFI score was 6.7 ± 1.6. Women who achieved clinical pregnancy had significantly higher EFI scores than those who did not conceive (8.2 ± 1.2 versus 6.0 ± 1.3; p < 0.001). An EFI cut-off of ≥7 predicted clinical pregnancy with a sensitivity of 95.8% and specificity of 52.3%, with an area under the curve (AUC) of 0.90 (95% confidence interval {CI}: 0.82-0.97). The hazard ratio for conception among women with an EFI of ≥7 was 19.2 (95% CI: 2.6-142.1; p = 0.004). Women with EFI scores of 9-10 demonstrated a 100% pregnancy rate within six months. The cumulative probability of non-ART pregnancy at six months was 33.3%. An ASRM score of <21 also demonstrated predictive capability with an AUC of 0.92. Conclusion EFI demonstrated strong predictive performance for non-ART pregnancy outcomes following laparoscopic surgery in women with endometriosis-associated infertility. The index may serve as a valuable clinical tool for individualized fertility counselling, prognostic assessment, and guiding decisions regarding expectant management versus early assisted reproductive intervention.