Combination of zygote andembryo morphology scoring couldaccurately aid to predict the outcomeof intra-cytoplasmic sperm injectionprocedures

ABSTRACT

This study was designed to examine the relationship between zygoteand embryo morphology as judged by Z-scoring and Embryo scoring systems, and to test whether these scores could be used to predict accurate-ly the outcome of cycles of intracytoplasmic sperm injection[ICSI] judged by detection of chemical pregnancy. The study comprised 78 infertile couples that had undergone ICSI. After ICSI procedure, oocytes were cultured and assessed for the presence of pronuclei after 16-18 h of incubation. Zygotes were scored for the position of pronuclei, position and type of nucleoli and cytoplasmic morphology, each parameter was awarded a scoreof 5 points. Embryos were scored for the blastomere volume and synchrony of cleavage, the level of multinucleation and the extent of fragmentation, each of parameter was awarded a score of 5 points. Zygotes and embryos awarded score of 15 were categorized as Z1 or E1, those scored10-14 were categorized as Z2 or E2 and those scored <10 were Z3 or E3.The establishment of a chemical pregnancy was considered as a positive beta-hCG test >20 IU/L at 12 days after embryo transfer and was consid-ered for evaluation of the predictability of the outcome of ICSI procedure. The mean number of oocytes retrieved was 7.1+/-2.6_patient and succeeded fertilization was reported in 422 of a total of 536 oocytes [80.6%].There were 113 zygotes [26.16%] of Z1 score, 186 zygotes [43.06%] of Z2 score and 133 zygotes [30.78%] of Z3 score; whereas, 101 embryos [23.38%] were of E1 score, 187 embryos [43.29%] were of E2 score and144 embryos [33.33%] were of E3 score. There was a positive significant correlation between the determined zygote and embryo scores, [p<0.001].Pregnancy was diagnosed in 19 patients [24.35%], 10 females [52.63%] had embryos morphologically graded Z1E1, 4 females [21.05%] had embryos' graded Z2E2, 2 females [10.52%] had embryos graded Z1E3 and the other 3[15.79%] had their embryos graded Z1E2, Z2E1 and Z3E1, respectively. Morphological scoring depending on both zygote and embryo scoring could predict the outcome of ICSI with specificity 91.77% and ac-curacy rate of 90.05%, while depending on zygote score alone the specificity and accuracy rates were 75.79% and 73.15%, respectively and depending on embryo score only specificity and accuracy rates were 78.4%and 77.77% with a significant difference in the predictability depending on combined scores compared to that depending on either zygote score[p<0.001] or embryo score [p<0.01]. It could be concluded that morphological scoring using combination of zygote and embryo scores aid to predict accurately the outcome of ICSI procedures