Negative Sliding Sign during Dynamic Ultrasonography Predicts Low Endometriosis Fertility Index at Laparoscopy

Endometriosis fertility index (EFI) is a robust tool to predict the pregnancy rate in patients with endometriosis who are attempting non-in vitro fertilization conception. However, EFI calculation requires laparoscopy. Newly established imaging techniques such as sliding sign, which is used to diagnose pouch of Douglas obliteration, could provide a promising alternative. The objective of this study was to investigate the practicality of using ultrasound data to predict a low EFI (score ≤6).

Observational study from a prospective registry (Endometriosis Pelvic Pain Interdisciplinary Cohort, clinicaltrials.gov #NCT02911090). Analyzed data were captured from December 2013 to June 2017.

Tertiary referral center at British Columbia Women's Hospital.

We analyzed data for 2583 participants from the Endometriosis Pelvic Pain Interdisciplinary Cohort. In this cross-sectional study, we included 86 women aged <40 years.

Dynamic ultrasonography for the sliding sign testing and EFI calculation during laparoscopic surgery.

Logistic regression was used to obtain receiver operating characteristic area under the curve (AUC) for the prediction models. Significance was p <.05. Patients with a negative sliding sign were older and had severe endometriosis and longer duration of infertility. Patients with a negative sliding sign had significantly lower total EFI scores and lower surgical factors scores than patients with a positive sliding sign. Logistic regression showed that a negative sliding sign and EFI historic factors score can predict an EFI score ≤6 (sensitivity = 87.9%, specificity = 81.1%, AUC = 0.93 [95% confidence interval, 0.88-0.98]). Adding the diagnosis of endometrioma to the previous prediction model resulted in AUC = 0.95 (95% confidence interval, 0.90-0.995), sensitivity = 84.8%, and specificity = 92.5%.

The sliding sign could be a potential alternative to the EFI surgical factors, and it could be used in combination with EFI historic factors and the diagnosis of endometrioma to predict an EFI score ≤6 for patients who are not scheduled for immediate surgery.