Received April 21, 2000
Accepted May 15, 2000

To relate the embryonic development in culture of long duration in sequencial medium, and evaluate the implantation rate and pregnancy. Embryonic culture with culture medi um G I :2/G2:2, for tive days. The expanded blastocysts rate found in our study was 14% . The rate of pregnancy and implantation were 28,9% and 14,9% respectively. There was no rate of pregnancy or implantation increased than in the related literature to the convencional medium. ln the patients wich expanded blastocysts were transferred the implantation rates and pregnancy increased. The culture conditions didn't just influence the implantation rates and pregnancy, but the quality of the ova is also important, because the good responders had better results.