Assessment of Embryo Quality by Morphologic Scoring System: Its Validity and Usefulness for Prediction of Pregnancy

Kim, Seung Ryong; Wood, Carl

Abstract

Aims: To study the validity of a scoring system in evaluating embryo quality and predicting pregnancy potential. The scoring system was formulated using morphologic parameters and cleavage rates. Embryos were scored between 0 and 10 according to morphologic criteria and cleavage rate. Materials and METHODS: The pregnancy results of 2,371 fresh embryos scored by this criteria and transferred between January 1991 and September 1992 in the Monash IVF Program, Melbourne, Australia were analysed for this study. RESULTS: Analysis of 2,371 fresh embryos scores from 926 consecutive transfers showed that intrauterine and multiple pregnancy rate increased significantly along with increased total score per transfer(p < 0.05). Pregnancy rate also increased from 10.7% to 21.6% as the number of embryos with a score of 7 or more(good embryo) increased from 0 to 3(p < 0.05). The well-known relationship between the number of embryos transferred and pregnancy rate was also found but this correlation could not seen when all of added embryos were scored less than 7. When all the embryos in a given transfer were scored less than 4(poor embryo), the pregnancy rate was near zero regardless of the number of embryos transferred. Conclusion: This study indicated that an embryo scoring system based on morphologic and cleavage rate criteria could be useful in selecting good quality embryos and predicting the pregnancy rate in an IVF/ET program.