Association between blastocyst morphology and outcome of single-blastocyst transfer

The aim of this study was to assess the ability of three individual blastocyst morphology parameters - expansion and hatching (EH) stage, inner cell mass (ICM) grade and trophectoderm grade - to predict outcome of a cycle with single-blastocyst transfer. The study was a secondary analysis of data prospectively collected in a large multicentre trial. A total of 618 intracytoplasmic sperm injection patients undergoing ovarian stimulation in a gonadotrophin-releasing hormone antagonist cycle with compulsory single-blastocyst transfer on day 5 were included. In the simple logistic regression analysis, all three blastocyst morphology parameters were statistically significantly (P < 0.005 for each) associated with positive human chorionic gonadotrophin, clinical and ongoing pregnancy rates and live birth rates, while only the ICM grade was significantly (P = 0.033) associated with early pregnancy loss rate. Blastocyst EH stage was the only significant predictor of live birth (P = 0.002) in the multiple logistic regression. In conclusion, although all three blastocyst morphology parameters were related to treatment outcome of fresh single-blastocyst cycles, selection of high-quality blastocysts for transfer should consider first the EH stage. Transfer of a blastocyst with ICM grade A may reduce the risk of early pregnancy loss. (c) 2013, Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.