INTEREST OF COCULTURES FOR EMBRYOS OBTAINED BY IN-VITRO FERTILIZATION- A FRENCH COLLABORATIVE STUDY

Go-cultures of human embryos, particularly,vith Vero cells, are used b y several French groups, mainly in cases of successive failures of imp lantation, In most cases coculture is continued until the blastocyst s tage, expanded if possible, A total of 1603 co-cultures have been perf ormed by 11 groups over a 2-year period. Of these, 41.8% of cleaved eg gs (day 2) reached the blastocyst stage at day 5 or day 6. The mean pr egnancy rate and implantation rate per transfer were 32.9 and 24.8% re spectively, which represented a significant improvement compared to th e transfer of 2 day old embryos, The rate of multiple pregnancies rema ined high (29.1%), which implies that there should be transfer of not more than two blastocysts. The rate of anomalies perceived at birth or in utero was not different from the rate observed in the general popu lation, taking account of the maternal age.