Leveling the playing field – embryo transfers after trophectoderm biopsy have similar outcomes in fresh and frozen cycles

Abstract

Centers performing trophectoderm biopsy (TB) with preimplantation genetic testing (PGT) routinely perform elective cryopreservation; however success rates with fresh day 6 transfer are largely unknown. Here we compare clinical outcomes of fresh vs. frozen embryo transfers (ET) of IVF-PGT cycles with TB. Retrospect cohort study. All non-donor transfers of embryos that underwent biopsy on day 5 (D5) or day 6 (D6) for PGT with fresh D6 or frozen ET since February, 2010 were included. All retrievals, biopsies and transfers occurred at a single academic center. Embryos biopsied prior to D5 or after initial cryopreservation were excluded. PGT included testing for 24 chromosomes in all cases and single gene in a subset of patients. Indications for embryo cryopreservation after TB included: OHSS, single gene testing, late embryo cavitation, prior failed fresh ET. Clinical pregnancy rates (CPR) and live birth rates (LBR) were calculated per ET. Data was analyzed using student's t test and χ2, with statistical significance defined as p’0.05. See Table 1.Table 1Comparison of cycle outcomes after PGT in fresh and frozen thawed transfersFresh transfers (n=32)Frozen transfers (n= 16)p valueAge (years)*37350.22Oocytes*15220.02ICSI a62.581.30.32Fertilization rate74.768.90.28Single gene testing (%)3.143.80.001Number of embryos transferred*1.31.20.67Positive hCG b7881.31Implantation rate54.768.80.32Clinical pregnancy rate58.181.30.34Miscarriage rate5.88.31Ongoing pregnancy and live birth rate53.1750.21a: % of cycles that utilized ICSI b: % of transfers with positive (’5mIU/mL) hCG; *: indicates mean. Open table in a new tab a: % of cycles that utilized ICSI b: % of transfers with positive (’5mIU/mL) hCG; *: indicates mean. This is the first comparison study, performed at a single center, to suggest similar clinical outcomes with fresh D6 transfer after PGT vs. cryopreservation after TB. Providers should be encouraged to individualize timing of ET, as fresh cycles appear to share similar success rates as frozen after PGT.