Poor morphology of inner cell mass increases birth weight and large for gestational age

Can inner cell mass (ICM) and trophectoderm morphological grading, especially ICM and trophectoderm graded C, affect perinatal outcomes?

A retrospective review of medical records of 8946 singletons delivered from vitrified-warmed single blastocyst transfer cycles between January 2009 and December 2020.

Inner cell mass graded C had a higher adjusted birth weight than ICM graded A (0.61 ± 1.06 versus 0.48 ± 1.06; P = 0.025). Large for gestational age (LGA) increased with decreasing ICM morphological grading (18.96%, 21.88% and 23.38%; grade B versus grade A, P = 0.013; grade C versus grade A, P = 0.036) (P < 0.025 was considered statistically significant for multiple pairwise comparisons). Linear regression analysis suggested that ICM morphological grading was significantly associated with adjusted birth weight, with grade C increasing adjusted birth weight compared with grade A (β 0.13, 95% CI 0.00 to 0.25, P = 0.043) (P < 0.05 was considered statistically significant for linear regression). Logistic regression analysis suggested that ICM morphological grading was significantly associated with LGA, with grade C increasing LGA compared with grade A (adjusted OR 1.37, 95% CI 1.03 to 1.81). Moreover, blastocysts with ICM graded C had a higher chance of being a male infant compared with ICM graded A (adjusted OR 1.32, 95% CI 1.04 to 1.68).

Inner cell mass morphological grading was significantly associated with adjusted birth weight and LGA. Poor ICM graded C increased birth weight and LGA.