Received October 21, 1998
Accepted February 16, 1999

Introduction: Several factors have been reported to influence the pregnancy rate during IVF cycles, including the cause of the infertility, age of the woman, stimulation protocol, number of oocytes retrieved, number of embryos transferred and the quality of the embryos. The objective of this work is evaluating the relationship between the embryo quality and the incidence of pregnancies. Material and Methods: Three hundred fifty one (35 1 )embryos transferred i n 1 00 couples who underwent an IVF program were analyzed. These couples were divided in 3 groups. Group A: 60 patients that received, between alI embryos grades, at least one embryo grade 1 (64,5 %). Group B : 20 patients that received, between some embryos grades, at least one embryo grade II, but none grade I (21,5%). Group C: 13 patients that received only embryos Grades III, IV and V (14,0%). Results: In groups in which the best embryos transferred was grade I and II, the clinical rates per ET were respectively better if compared with the group that received only embryos grades III, IV and V. Conclusion: The implantation rate of transferred embryos is directly correlated with the morphological scoring.