[Embryo vitrification: French clinical practice analysis for BLEFCO]

Frozen thawed embryo transfer is currently an important part of present-day assisted reproductive technology (ART) aiming at increasing the clinical pregnancy rate per oocyte retrieval. Although slow freezing method has been the reference during 2 decades, the recent years witnessed an expansion of ultrarapid cryopreservation method named vitrification. Recently in France, vitrification has been authorized for cryopreserving human embryos. Therefore BLEFCO consortium decides to perform a descriptive study through questionnaires to evaluate the state of vitrification in the French clinical practice. Questionnaires were addressed to the 105 French centres of reproductive biology and 60 were fully completed. Data analysis revealed that embryo survival rate as well as, clinical pregnancy rate were increased after vitrification technology when compared to slow freezing procedure. Overall, these preliminary data suggest that vitrification may improve ART outcomes through an increasing of the cumulative pregnancy rate per oocyte retrieval.