Three-dimensional endometrial volume estimation as a predictor of pituitary down-regulation in an IVF-embryo transfer programme

To examine the role of three-dimensional (3D) volume estimation in predicting pituitary down-regulation in an IVF-embryo transfer programme, 46 women were treated with buserelin acetate for down-regulation prior to and concomitantly with ovarian stimulation. Receiver operating characteristic (ROC) curve analysis was used for statistics, The area under the curve (AUC) provides a measure to show how good (AUC close to 1) or how poor (AUC close to 0.5) a test is. If down-regulation was defined as oestradiol <40, <60 or <80 pg/ml, the AUC of 3D-ultrasound was 0.57, 0.83 and 0.97 respectively. The highest sensitivity (100%) and specificity (93.2%) of 3D-ultrasound was achieved if down-regulation was defined as oestradiol <80 pg/ml (n = 44), with an endometrial volume of 1.9 ml. If down-regulation was defined as oestradiol <60 pg/ml (n = 42) the best combination of highest sensitivity (95.2%) and specificity (75.0%) was obtained with an endometrial volume of 1.9 ml. The comparison of 3D volume calculation with endometrial thickness measurement revealed no significant difference in predicting down-regulation. 3D volume estimation provides a new tool for diagnosing relative hypo-oestrogenism or down-regulation, but it was not superior to two-dimensional ultrasound.