[Cocultures in France: situation in 1995. Geff-BLEFCO]

Co-cultures of human embryos, in particular those concerning Vero cells, are used by French teams mainly in case of repeated failures of implantation. Most of them continue the co-cultures until obtaining one blastocyst, expanded in possible. 1,603 co-cultures have been reported by 11 groups during 2 years (1993-1994). 41,8% of cleaved eggs (day 2) reached the blastocyst stage. The pregnancy rate per transfer was 32,9%; the implantation rate of blastocysts was 24,8% which represents a significant improvement when compared to the implantation rate of 2 days old embryos. The rate of multiple pregnancies remained high (29,1%), which would incite to transfer not more than 2 blastocysts. The rate of anomalies at birth or detected in utero, was not different of the rate observed in the general population, taking account of the maternal age.