Impact of double trophectoderm biopsy on reproductive outcomes following single euploid blastocyst transfer.

OBJECTIVES: To study the effect of double trophectoderm biopsy on clinical outcomes following single euploid blastocyst transfer. STUDY DESIGN: Retrospective cohort study of 2046 single euploid frozen-thawed blastocyst transfers from January 2015 to June 2022 in a single centre. All patients undergoing a frozen-thawed embryo transfer (FTET) cycle with euploid blastocysts, biopsied for any indication, were included. The outcomes were compared for blastocysts which were biopsied and vitrified once (Group 1, n = 1684), biopsied once but vitrified twice (Group 2, n = 312) and biopsied and vitrified twice (Group 3n = 50). We adjusted for confounders and performed subgroup analysis for PGT-A, PGT-M and PGT-SR cycles. The primary outcome was live birth rate. Secondary outcomes included pregnancy, clinical pregnancy, birthweight and sex ratio. RESULTS: After adjusting for confounders (previous failed euploid implantations, embryo quality and day of biopsy), embryos which were biopsied twice had lower OR for clinical pregnancy (0.48, CI 0.26-0.88, p = 0.019) and for live birth (0.50 CI 0.27-0.92, p = 0.025) compared to controls. Embryos which were biopsied once but vitrified twice had no different ORs for all reproductive outcomes compared to controls. No significant difference was observed for neonatal birthweight or sex ratio amongst the three groups. This is a retrospective single centre study with inherent bias and results may not be transferable to all settings. CONCLUSION: This study is the largest to date assessing the outcomes of FTET cycles following double trophectoderm biopsy. The results are in keeping with the existing literature and can be incorporated into patient counselling. Whilst double biopsy seems to adversely impact LBR, it is only one of the many factors that can affect success rates. The subfertility background and embryo characteristics should not be overlooked. This study provides reassuring evidence since double biopsied embryos still result in live births with no difference in sex ratio or birthweight. However, long term follow up of the off-springs is lacking and should be reported in future studies.

The First Livebirth Using Warmed Oocytes by a Semi-Automated Vitrification Procedure.

BACKGROUND: The first successful livebirth using warmed oocytes (vitrified by the GAVITM system) is reported in this paper. Embryologists throughout the world have vitrified oocytes using a manual technique which is susceptible to error and variation. In this era of automated laboratory procedures, vitrification was made semi-automatic by using the GAVITM system. CASE PRESENTATION: Donor oocytes were initially vitrified using the GAVITM system. They remained in the clinic's oocyte bank until they were allocated to the patient. Donor oocytes were warmed as per Genea BIOMEDX protocol and inseminated to create embryos. Resulting embryos for the 42-year-old patient were cultured to the blastocyst stage, biopsied to perform PGT-A, using next generation sequencing and subsequently vitrified. The patient underwent a single euploid transfer in a frozen embryo transfer cycle which resulted in a healthy livebirth. CONCLUSION: The introduction of a semi-automated system should minimize the risk to the oocytes, standardize the procedure worldwide and potentially reduce the laboratory time taken by the embryologists. This case report demonstrates the safety of the technology used for vitrification, but larger randomized studies need to be performed to demonstrate the safety and efficacy of newer technologies like the GAVITM system before adopting it as a standard laboratory procedure.