PROSPECTIVE EVALUATION OF SIMPLE MORPHOLOGICAL CRITERIA FOR EMBRYO SELECTION IN DOUBLE EMBRYO-TRANSFER CYCLES

Preventing the occurrence of high-rank multiple pregnancies without re ducing the pregnancy rate remains a high priority of in-vitro fertiliz ation and embryo transfer programmes, Our previous study demonstrated that, if there is at least one embryo with a good morphological grade, then the transfer of two (a double embryo transfer) instead of three embryos does not result in a lower pregnancy rate, and that the influe nce of the number of embryos transferred becomes significant only when poor-quality embryos are transferred, This result allowed us to emplo y the simple policy of systematically selecting double embryo transfer cycles without affecting the pregnancy rate, Since January 1994, when patients <37 years of age had more than two embryos available for tra nsfer, only two instead of three embryos were transferred if at least one of the embryos demonstrated a good morphological grade, After a 1 year application of this policy, of the 147 cycles (group A) that fulf illed the above criteria, two embryos were transferred in 92 cycles, w hile three embryos were transferred in the other 55 cycles, The result s of these cycles were compared to those of the control 144 cycles (gr oup B) in which three embryos were transferred, prior to the applicati on of this policy, The on-going pregnancy rates and the incidence of m ultiple and triplet pregnancies were 24% and 28%, 22% and 23%, and 2% and 9% in groups A and B respectively. The rates were not significantl y different. In conclusion, although our prospective trial demonstrate d a tendency of decreasing pregnancy rate and an invariable incidence of multiple pregnancies, the very low occurrence of triplets during th is period indicated that this policy provided a practical compromise b etween achieving a high pregnancy rate and an acceptable incidence of triplet pregnancies.