Fig. 4

ROC curve of endometrial echogenicity value on OPU + 1,2,3 for successful clinical pregnancy. The areas under the ROC curve were 0.738(95%CI:0.656–0.819), 0.765(95%CI: 0.688–0.842), 0.714(95%CI:0.624–0.804) respectively on OPU + 1, OPU + 2 and OPU + 3. Endometrial echogenicity value on OPU + 2 had the most predictive value, and the cutoff value was 76.5%. The sensitivity was 61.3% and the specificity was 82.0%