Trophectoderm grade as a predictor of beta human-chorionic gonadotropin rise in early pregnancy

To evaluate the association, if any, between the grade of the trophectoderm (TE) and the rate at which β-human-chorionic gonadotropin (β-HCG) rises in early pregnancy.

This is a retrospective cohort study including 1116 singleton clinical pregnancies resulting from in vitro fertilization with single day 5 blastocyst transfer at an academic fertility center. TE quality was assessed by trained embryologists employing standard criteria. Three groups were formed based on the TE grade: grade A (n = 358), grade B (n = 628), and grade C (n = 130). Main outcome measure was the rise (%) in serum levels of β-HCG (days 12 to 14 post embryo transfer), using the following formula [(β-HCG D14 - β-HCG D12) * 100/β-HCG D12].

Fresh embryo transfers accounted for 64.1% of the population. Overall, in adjusted models there were no significant differences in the β-HCG% rise when comparing the TE grade C group to TE grade A [adjβ (95%CI): 10.09 (- 0.05, 20.22)] or when comparing TE grade Β group to TE grade A [4.46 (- 2.97, 11.88)]. When the analysis was restricted to fresh embryo transfers, significant differences were observed in the % rise of β-HCG when comparing the TE grade C group to TE grade A [adjβ (95%CI): 21.71 (5.67, 37.74)], but not when comparing the TE grade B group to TE grade A [2.68 (- 5.59, 10.95)]. In frozen transfers, there were no significant differences.

TE grade appears to impact early pregnancy serum β-HCG levels in the setting of a fresh day 5 embryo transfer, even after adjusting for potential confounders.