title: Association between blastocyst morphology and outcome of single-blastocyst transfer.
abstract: 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. Choosing the embryo(s) with the best implantation potential is essential for securing each couple the highest chance of achieving pregnancy after assisted reproduction. The selection of embryo(s) for transfer at the blastocyst stage is based on morphology parameters of expansion and hatching stage, inner cell mass grade and trophectoderm grade. The aim of this study was to assess the relative impact of each parameter in predicting the probability of a successful outcome. The study was a secondary analysis of data prospectively collected in a large multicentre trial. A total of 618 patients who underwent single-blastocyst transfer on day 5 were included. Statistical analysis showed that all three blastocyst morphology parameters were significantly associated with positive human chorionic gonadotrophin (βHCG), clinical and ongoing pregnancy rates and live birth rates. Only the inner cell mass grade was significantly associated with early pregnancy loss between the positive βHCG test and confirmation of ongoing pregnancy 10-11weeks after transfer. The expansion and hatching stage was the only significant predictor of live birth in the multiple logistic regression analysis. 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 expansion and hatching stage. Transfer of a blastocyst with inner cell mass grade A may reduce the risk of early pregnancy loss.
authors: Reproductive Medicine, Gent University Hospital, Gent, Belgium.
authors: Etienne
authors: E
authors: Van den Abbeel
authors: Basak
authors: B
authors: Balaban
authors: Søren
authors: S
authors: Ziebe
authors: Kersti
authors: K
authors: Lundin
authors: Maria José Gómez
authors: MJ
authors: Cuesta
authors: Bjarke Mirner
authors: BM
authors: Klein
authors: Lisbeth
authors: L
authors: Helmgaard
authors: Joan-Carles
authors: JC
authors: Arce
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000166:cytology*; D053624:Blastocyst Inner Cell Mass / Q000648:ultrastructure; D005260:Female; D006801:Humans; D016015:Logistic Models; D015337:Multicenter Studies as Topic; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D016032:Randomized Controlled Trials as Topic; D056826:Single Embryo Transfer
keywords: blastocyst morphology; early pregnancy loss; live birth; prediction; single-embryo transfer