Clinical outcomes after transfer of blastocysts derived from frozen–thawed cleavage embryos: a retrospective propensity-matched cohort study

Purpose To evaluate the clinical outcomes after fresh transfer of blastocysts cultured from vitrified–thawed cleavage embryos (VTCE) compared with conventional frozen–thawed blastocysts transfer (FBT), or with the usual fresh blastocysts transfer (FRBT). Methods A total of 155 cycles undergoing fresh transfer of VTCE blastocysts, 4904 cycles undergoing FBT, and 1014 cycles undergoing FRBT were retrospectively analyzed from August 2014 to July 2017. Pregnancy, delivery, and neonatal outcomes were compared after propensity score matching. Results VTCE blastocysts’ transfer resulted in a lower risk of early miscarriage (8.82% versus 19.70%, P