Prediction of pituitary down-regulation by evaluation of endometrial thickness in an IVF programme

The aim of this retrospective study was to determine whether pituitary down-regulation after gonadotrophin-releasing hormone analogue (GnRHa) administration can be accurately predicted by transvaginal ultrasonographic measurement of endometrial thickness in the presence of menstruation. All cycles of an IVF/intracytoplasmic sperm injection programme in which a long protocol of GnRHa was used for ovarian stimulation were analysed. Overall, 209 patients underwent 223 treatment cycles. Using a serum oestradiol concentration of 50 pg/ml as a cut-off point, the sensitivity, specificity, predictive value and false positive and false negative values were calculated for prediction of pituitary down-regulation from endometrial thickness measurements. Pituitary down-regulation was achieved in 223 treatment cycles in 180 patients (80%). The best combination of the highest specificity (71.7%) and sensitivity (62.5%) is achieved with a linear appearance of the endometrium. Therefore, ultrasonographic measurement of endometrial thickness should be used in combination with serum oestradiol concentration in estimating pituitary down-regulation after GnRHa. In conclusion, the linear appearance of endometrium can be as reliable as serum oestradiol concentration in prediction of pituitary down-regulation after GnRHa.