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). Ninety-four per cent of surviving embryos w ere transferred to the parental couple, 6% were thawed to conclude the ir storage while embryo donation remained exceptionnal (0.2%). Fifty-f ive per cent of all thawed embryos survived the freeze-thaw procedure. However, only 3.5% of transferred embryos achieved full-term developm ent (as compared to 9% for unfrozen embryos). Thus, embryo freezing ef ficiency remains low but highly variable among different centers. Ther efore, cryopreservation has led to the birth of more than 1 200 babies and for several group, has contributed up to 22 % of IVF deliveries. The variability observed in the results can be largely related to the adequacy of programmable freezers. Indeed, 68% of frozen embryons surv ived after thawing in case of manual seeding (15% pregnancy per transf er) versus 42% in case of automatic seeding (9% pregnancy per transfer p < 0,001). Freezing has no adverse effect on the rate of anomalies a t birth (1,8%).