Embryo freezing: status survey in France (1985-1993) . Federation of BLEFCO
Contraception Fertilite Sexualite 24(9): 674-677
1996
ISSN/ISBN: 1165-1083 PMID: 8998516 Document Number: 466906
The French Federation of IVF Biologists (BLEFCO) reports the first survey on the fate of 102812 human embryos frozen in France during a nine-year period (1985-1993). 94% of surviving embryos were transferred to the parental couple, 6% were thawed to conclude their storage while embryon donation remained exceptional (0.2%). 55% of all thawed embryos survived the freeze-thaw procedure. However, only 3.5% of transferred embryos achieved full-term development (as compared to 9% for unfrozen 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 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 embryos survived after thawing in case of manual 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%).