Low TGF-β and Embryo Implantation in the Context of Assisted Reproductive Technology: Confirmation of a Biomarker Predictive of Success and Characterization of the Immune Microenvironment.

Infertility affects about one in seven couples in France. Beyond the medical and personal challenges, it has major societal implications. In vitro fertilization (IVF) offers hope to these couples, but success rates remain modest (about 30% per embryo transfer). The failure of embryo implantation is multifactorial. Among the factors involved, immune status at the time of embryo transfer plays a central role. Embryo transfer induces an acute pro-inflammatory immune response, and inadequate regulation of this response could compromise implantation. The investigators have previously identified a promising immune biomarker: TGF-β (Transforming Growth Factor Beta). In a prospective cohort of 255 patients undergoing frozen embryo transfer, the investigators demonstrated that low circulating levels of TGF-β following nonspecific stimulation of immune cells on the day of embryo transfer were associated with a significant increase in the likelihood of implantation and live birth. These results now require independent validation in a new cohort to establish their robustness and explore potential clinical applications. The investigators hypothesize that measuring TGF-β concentration following stimulation can predict the success of embryo implantation.