Purpose: to compare the embryonic development obtained with two different culture methods (sequential medium or coculture in Vero cells). Methods: oocytes were recovered from 110 patients and submitted toin vitro fertilization. The embryos of half of the patients were co-cultured with Vero cells and the embryos of the other half were cultured in sequential G1:2/G2:2 medium for five days. The embryos were transferred on the 5th day after fertilization after morphological evaluation for the determination of blastula formation rate. Pregnancy was defined by ultrasonography and a fetal heartbeat was determined 13 weeks after transfer. Results: the expanded blastocyst rate found in our study was 15.9 and 14% with Vero cells and G1:2/G2:2, respectively. With Vero cells 36.0% of patients became pregnant and the implantation rate was 18.9%. When G1:2/G2:2 was used, the pregnancy and implantation rates were 28.9 and 14.9%, respectively. Only 17 patients had blastocysts after coculture in Vero cells, with a 76.5% pregnancy rate and a 63.5% implantation rate. When embryos were cultured in G1/G2, 21 patients presented blastocysts and the pregnancy and implantation rates were 57.1 and 76.0%, respectively. Conclusion: there was no significant difference in pregnancy or implantation rates between the 2 types of culture. When expanded blastocysts were transferred, the implantation and pregnancy rats increased with both culture types. In these patients, regardless of the type of culture used, a larger number of oocytes was obtained, suggesting that the implantation and pregnancy rates are affected not only by the culture conditions but also by the quality of the eggs, since "good responders" had better results.
In vitro fertilization; Infertility; Embryo culture
