PROGNOSTIC VALUE OF BLASTOCYST GRADE AFTER FROZEN EUPLOID EMBRYO TRANSFER IN PATIENTS WITH RECURRENT PREGNANCY LOSS

To determine if trophectoderm (TE) grade or inner cell mass (ICM) grade have predictive value after euploid frozen embryo transfer (euFET) among RPL patients.

Retrospective cohort study.

Single fertility center, 2012-2018.

Patients with ≥ 2 prior pregnancy losses performing PGT-A with ≥1 euploid embryo for transfer.

All patients underwent ICSI, trophectoderm biopsy, blastocyst grading and vitrification, and single euFET. Outcome of the first transfer was recorded.

Live birth (LB) and clinical miscarriage (CM) rates.

660 euFET were included. In a binomial logistic regression analysis accounting for age, BMI, AMH and day of blastocyst biopsy, ICM grade C was not significantly associated with odds of live birth (aOR 0.50, 95% CI 0.24-1.02 p=0.057), miscarriage (aOR 1.67, 95% CI 0.56-5.00, p=0.36) or biochemical pregnancy loss (aOR 1.58, 95% CI 0.53-4.75, p=0.42). TE grade C was significantly associated with odds of live birth (aOR 0.49, 95% CI 0.28-0.86, p=0.01) and was not associated with odds of miscarriage (aOR 2.00, 95% CI 0.89-4.47, p=0.09) or biochemical pregnancy loss (aOR 1.85, 95% CI 0.77-4.44, p=0.17). Blastocyst grade CC had significantly lower LB rate compared to all other blastocyst grades (p<0.05, chi-square analysis).

Embryo grade CC and TE grade C are associated with decrease in odds of LB after euFET in RPL patients. Embryo grade is not associated with odds of CM in this cohort of RPL patients, suggesting that additional embryonic or uterine factors may influence risk of pregnancy loss.