Clinical and perinatal outcomes of fully hatched versus not fully hatched blastocysts

To compare the clinical and perinatal outcomes following the transfer of fully hatched (FH) and not fully hatched (NFH) blastocysts in assisted reproductive technology.

This study enrolled women undergoing their first oocyte retrieval cycle with a freeze-all strategy, provided that they had at least one transferrable embryo. Patients were classified into preimplantation genetic testing for aneuploidy (PGT-A) cycles and non-PGT cycles, including thawed blastocysts (thawed-blast) and blastocysts cultured from thawed day 3 embryos (blast-thawed-d3). We compared pregnancy and perinatal outcomes following the transfer of an FH blastocyst or an NFH blastocyst. The primary outcome was the live birth rate. In PGT-A cycles, multivariate logistic and linear regression models were used to adjust for covariates. In thawed-blast and blast-thawed-d3 cycles, baseline characteristics between the FH and NFH groups were balanced via propensity score matching.

In PGT-A cycles, no significant differences were detected between the FH and NFH groups in implantation rate (67.5% vs. 66.5%, adjusted odds ratio [aOR] 1.17; 95% confidence interval [CI] 0.98-1.39), miscarriage rate (15.0% vs. 14.1%, aOR 0.95; 95% CI 0.72-1.27), live birth rate (56.5% vs. 56.4%, aOR 1.13; 95% CI 0.96-1.34), or perinatal outcomes. In thawed-blast and blast-thawed-d3 cycles, no significant differences were observed in pregnancy and perinatal outcomes between the FH and NFH groups.

In both PGT-A and non-PGT cycles, pregnancy and perinatal outcomes following transfer of FH and NFH blastocysts were comparable.