Resumen de The art laboratory through the prism of the cumulative pregnancy rate
Even today, the success of IVF is often expressed in terms of live birth per fresh cycle or per embryo transfer. With increasingly different treatment strategies (as freeze-all, PGT with trophectoderm biopsy), the need for more accurate parameters of IVF success has been imposed. Cumulative pregnancy rate (CPR), or even better cumulative live birth rate (CLBR) per oocyte retrieval is more meaningful as cryopreservation has become an integral part of IVF treatment. Moreover, CLBR allows much better comparison of IVF outcome between centers. However, even the definition of CLBR seems a challenge, the term being used differently in different reports, making comparison between reports unreliable. Strictly considered, all embryos from one stimulation cycles should be thawed for transfer, which may take a period of time, and many of them will never be used by the patients.
