Use of endometriosis fertility index to predict non-ART pregnancy and live birth after endometriosis surgery based on optimal stratification

Abstract

Backround: The EFI, which was previously developed and validated externally, has shown predictive accuracy of non-ART pregnancy following surgery in infertile women with endometriosis. But up to now it was less accurate among the patients with lower scores based on the classification of the original literature. In addition, so far the only study has reported a strong association between the EFI and the live birth. However, the analysis of that study was done in women undergoing surgery rather than in those who had conceived post-operatively. Methods: 501 infertile women undergoing laparoscopic treatment of endometriosis were recruited and followed up for post-operative pregnancy outcomes. The associations of EFI with non-ART pregnancy and with live birth were investigated with survival analysis and the Cochrane-Armitage test. The optimal cut-offs for EFI were determined using the Maximally Selected Rank Statistics (Maxstat). Result(s): The follow-up rate was 92.4% with a mean duration of 38.5 months (range: 14.4-67.4 months). A total of 270 women (58.3%) conceived without ART, 187 (69.3%) had a live birth. A statistically significant association of EFI with non-ART pregnancy rate was observed (hazard ratio: 1.29, 95% confidence interval: 1.19-1.36; 95% confidence interval: 0.57-0.65). The Maxstat method suggested optimal EFI strata of 4, 6 and 8. The cumulative non-ART pregnancy rates 3 years after surgery were 15.0%, 47.1%, 67.6% and 73.6% for EFI scores of 0-4, 5-6, 7-8 and 9-10, respectively (Log-rank p < 0.001). No statistical differences were seen in the live birth rates and the time to pregnancy in the four EFI groups. Conclusion: The EFI is predictive of post-operative non-ART pregnancy but not live birth among non-ART pregnancies. ART might be advisable to women with an EFI score <4 immediately after surgery and to women who have not achieved non-ART pregnancy after 12 months despite a high EFI.