Blastocyst morphology has no relationship with serum β-hCG levels and live birth rates once pregnant.

Objective: What is the role of blastocyst morphology on day16 β-hCG serum levels and pregnancy outcomes among patients who conceived through IVF cycles with single fresh Gardner's scored blastocyst transfers.

Study Design: A retrospective cohort study conducted at a single academic fertility center between January 2013 and December 2017. A total of 643 pregnancies were included in the study.

Results: The patients were divided into 5 groups according to Gardner's blastocysts grade of the ICM and the TE (grade), and into 4 groups according to blastocyst Gardner's degree of blastocoel expansion (stage). No significant differences were found between the different morphologic groups and day16 β-hCG serum levels, clinical pregnancy rates and live births. A weak significant correlation was observed between Gardner's blastocysts grade and day 16 β-hCG (Correlation Coefficient r= -0.098, p = .014) this correlation remained significant after controlling for confounders. (r= -0.099 p = . 013). A weak significant correlation was observed between Gardner's stage and day 16 β-hCG (Correlation Coefficient r = 0.086, p = 0.029) this correlation lost significance after controlling for confounders. (r = 0.055, p = 0.340). When evaluating predictors of live birth using multivariate logistic regression, blastocyst grade (p = 0.33) and stage (p = 0.65), at transfer, were not associated with live births, when controlling for confounding effects.

Conclusion: Once the patient conceives after IVF with single blastocyst, none of the morphological parameters have a strong impact on the day16 serum level of β-hCG. Among women who conceived, blastocyst grade and stage were not associated with live births.