O-092 Does embryo biosensing really determine endometrial fate decisions at implantation?

Abstract Implantation depends on bi-directional communication between the blastocyst and endometrium. Encoded in this is information maternal embryonic fitness, which turn can lead to activation of species-specific reproductive suppression mechanisms. For example, blastocysts over 130 mammals, although not humans, respond presence or absence specific endocrine endometrial cues by entering exiting diapause, a state suspended animation that leads postponement implantation. By contrast, embryo biosensing selection depend endometrium first receiving decoding fitness from conceptus then either promoting implantation initiating rapid tissue breakdown, thus limiting investment into failing pregnancy. Importantly, relies physiological mechanisms sense deleterious (internal/external) cues, fundamentally different failure caused disease trauma. Nevertheless, easily conflated with pathology. repeated low-fitness IVF embryos diagnosis ‘recurrent failure’, an ill-defined clinical label, often spurs uninformative investigations ineffective ad-hoc treatments. On other hand, pathological relaxation at causes early pregnancy loss, frequency affected cycles determining age-independent recurrence risk miscarriage. In presentation, I will elaborate cellular control selection, highlight consequences, discuss emerging strategies for pre-pregnancy optimisation Trial registration number XXXX