Kyoko Higuchi

BACKGROUND: Although the number of frozen-thawed blastocysts transfer is increasing worldwide, the live birth rate following blastocyst transfer using assisted reproductive technology remains at 30-60%. Thus, improving the pregnancy rate per transfer is an urgent issue. In a previous retrospective study, we evaluated the use of granulocyte-macrophage colony-stimulating factor (GM-CSF)-containing medium for recovery culture to improve the outcomes of frozen-thawed blastocyst transfers. The results demonstrated that the live birth rates increased by approximately 10% following recovery culture in the GM-CSF-containing culture medium. This study aims to prospectively evaluate whether GM-CSF-containing blastocyst recovery culture following thawing increases live birth. METHODS: This is a multicenter, randomized, parallel-group, active-controlled, single-blind trial. The recruitment target is 750 participants meeting the criteria. Enrolled patients are randomized 1:1 to the GM-CSF-containing culture medium group (test group) or the non-GM-CSF-containing culture medium group (control group). The blastocyst recovery culture after warming was defined as an intervention in this study; frozen-thawed blastocysts will be cultured for 3-7 h in GM-CSF-containing medium (test group) or medium without GM-CSF (control group) followed by blastocyst transfer. The primary outcome will be live birth. We will also evaluate embryo transfer outcomes as secondary efficacy endpoints and evaluate perinatal and neonatal outcomes as a safety endpoint. DISCUSSION: This is the first large-scale prospective study to investigate the efficacy of a GM-CSF-containing medium for frozen-thawed blastocyst transfer. The study findings will provide evidence regarding the efficiency of GM-CSF-containing medium for blastocyst recovery culture after warming. TRIAL REGISTRATION: Japan Registry of Clinical Trials jRCT1040240159. Registered on January 6, 2025.

PURPOSE: To evaluate the feasibility and performance of spent culture medium (SCM)-based non-invasive pre-implantation genetic testing for aneuploidy (niPGT-A) after 8 h of post-warming in vitrified-warmed human blastocysts, and to determine whether post-amplification library concentration improves SCM-based result interpretation. METHODS: This study included 26 discarded vitrified-warmed blastocysts from 17 patients. After 8 h of post-warming culture, SCM was collected and analyzed by next-generation sequencing together with trophectoderm (TE) biopsy samples and whole blastocysts (WB). Concordance at the chromosome and category levels was evaluated between SCM and WB and between TE biopsy and WB, and the association of library concentration with performance and euploid probability was assessed. RESULTS: SCM analysis was informative in 92.3% (24/26) of embryos. Chromosome-level concordance with WB was lower for SCM than for TE (30.8% vs. 57.7%), whereas category-level concordance was 69.2% for SCM and 76.9% for TE. Combining SCM category with library concentration improved prediction of euploid embryos (AUC 0.9527 vs. 0.8077, p = 0.0158). The leave-one-out cross-validated AUC of the combined model was 0.896. CONCLUSIONS: SCM-based niPGT-A after 8 h of post-warming culture is feasible in vitrified-warmed human blastocysts. Library concentration improves interpretation of SCM-based results and may help identify embryos likely to be euploid.