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P–147 The impact of blastocyst morphological parameters on live birth and singleton birthweight in single blastocyst transfer cycles


 
 
 Does blastocyst morphological parameters: blastocyst expansion degree(Expansion), inner cell mass (ICM), and trophectoderm (TE) grades affect live birth and singleton birthweight in single blastocyst transfer cyles?
 
 
 
 The effects of blastocyst morphological parameters on live birth and singleton birthweight are different between biopsied blastocysts cycles and non-biopsied blastocysts cycles.
 
 
 
 It has been known that blastocysts with highest scores for three blastocyst morphological parameters achieve highest pregnancy rates, however, very few studies have comparatively analysed the effect of individual parameters on live birth and singleton birthweight about single blastocyst transfer cycles.
 
 
 
 This retrospective study involved all single blastocyst transfers cycles and their live birth outcome and singleton birthweight during the period from January 2014 to August 2019 at a tertiary care center.
 
 
 
 A total of 28515 single blastocyst transfer cycles were available for analysis and were divided into four groups: biopsied blastocysts cycles (BBC), thawed blastocysts cycles(TBC), blastocysts from thawed cleavage embryos cycles(BTCEC) and fresh blastocysts cycles(FBC). The primary outcome were live birth and singleton birthweight. Multiple logistics regression and linear regression analyses were respectively performed to investigate the effect of blastocyst morphological parameters on live birth and birthweight after adjusting potential confounders.
 
 
 
 While analyzing the effect on live birth, we found that live birth of grade B ICM were lower than grade A ICM , live birth of grade C TE were lower than grade A TE and Expansion doesn’t matter. Those result were same in three kinds of non-biopsied cycles. While all three parameters were statistically independently significant in biopsied blastocysts cycles.
 While analyzing the effect on singleton birthweight, only Expansion was found to be statistically significant in biopsied blastocysts cycles, and birthweight of Expansion grade 5 was lower than Expansion grade 6(P = 0.005),with a mean difference of 57g(3375.12±527.91 versus 3318.42±510.33). Limitations, reasons for caution: Most blastocysts with poor grade, especially ICM grade C, were not transferred, then the effect of poor grade such as ICM grade C were still unknown.
 Wider implications of the findings: The study identified the association between blastocyst morphological parameters and live rate and compared the relative importance of three parameters in different kind of cycles through large size comparative analysis, which would help selecting high-quality embryos for transfer.
 
 
 
 Not applicable
