Autologous bone marrow mesenchymal stem cell mitochondrial transplantation in recurrent assisted reproductive technology failure: a randomized controlled trial

• Autologous BMSC mitochondrial transplantation during ICSI does not improve clinical pregnancy or live birth rates in unselected patients with recurrent ART failure. • MIT transiently accelerates early embryonic cleavage (3-cell and 5-cell stages) but this morphokinetic change does not translate into improved embryo quality or clinical outcomes. • Long-term follow-up of 23 live births shows no adverse effects, supporting the safety of autologous BMSC mitochondrial transfer. • Oocytes with ≥70% transferable embryos after MIT exhibit a higher burden of medium-frequency mtDNA point mutations, suggesting a potential predictive biomarker for patient selection.