Biological relevance of trophectoderm morphology: initial β-hCG measurements correlate with trophectoderm grading on euploid frozen embryo transfers

Objective To analyze the correlation between TE grading and initial β-hCG serum level after single euploid embryo transfer. Secondarily, to explore the association between TE grading with subsequent IVF outcomes. Design Retrospective cohort analysis. Setting Single, academic, private infertility and assisted reproductive care institute. Patients or other participants Infertility patients who underwent a single euploid embryo transfer that resulted in a positive pregnancy test. Intervention(s) β-hCG measurements. Main outcome measure(s) Correlation between TE grade with first β-hCG measurement. Second outcome measurements included ongoing pregnancy, biochemical pregnancy loss, and clinical pregnancy loss rates. Results 2,798 cases were analyzed. A significant difference in initial β-hCG measurement among groups (TE A: median 143.4 mIU/mL IQR 79.2–211.2; TE B: 119 mIU/mL IQR 57.1–177.8; TE C: 82.4 mIU/mL IQR 36.3–136.4, p ≤ 0.0001) was observed. There was a significant correlation found between the TE grade and β-hCG measurements ( p ≤ 0.0001, r 2 = 0.10). TE grade was not associated with higher odds of biochemical pregnancy loss (TE A vs. TE B: aOR 1.01 CI95% 0.97–1.05; TE A vs. TE C: aOR 1.03 CI95% 0.98–1.08), or higher odds of clinical pregnancy loss (TE A vs. TE B: aOR 1.02 CI95% 0.98–1.05; TE A vs. TE C: aOR 1.03 CI95% 0.98–1.07). Conclusions In patients with euploid embryos, TE grade correlates with the first pregnancy test measurement of β-hCG. We propose this finding helps to appoint a relevant link between morphology assessment and early embryo development in vivo.