HUMAN EMBRYO FREEZING - STATEMENT IN FRAN CE (1985-1993)

The French Federation of IVF Biologists (BLEFCO) reports the first sur vey on the fate of 102 812 human embryos frozen in France during a nin e-year period (1985-1993). 94% of surviving embryos were transferred t o the parental couple, 6% were thawed to conclude their storage while embryon donation remained exceptionnal (0,2%). 55% of all thawed embry os survived the freeze-thaw procedure. However, only 3,5% of transferr ed embryos achieved full-term development (as compared to 9% for unfro zen embryos). thus, embryo freezing efficiency remains low but highly variable among different centers. Therefore, cryopreservation has led to the birth or more than 1200 babies and for several group, has contr ibuted up to 22% of IVF deliveries. The variability observed in the re sults can be largely related to the adequacy of programmable freezers. Indeed, 68% of frozen embryos survived after thawing in case of manua l seeding (15% pregnancy per transfer) versus 42% in case of automatic seeding (9% pregnancy per transfer p <0,001). Freezing has no adverse effect on the rate of anomalies at birth (1,8%).