Search

Objective: In order to study the eventual impact on fertilization and embryo characteristics of the microinjection procedure we compared the quality of the embryos obtained by ICSI with those of in vitro fertilization with male factors (MF IVF)., Material and Methods: One hundred thirty-four cycles of IVF treatment (group 1) were selected with oligoasthenozoospermia according to WHO criteria with a total number of motile spermatozoa between 500,000 and 1 million. One thousand eighty-eight mature oocytes and 486 embryos were obtained. One hundred forty-three cycles of intracytoplasmic sperm injection (group 2) were performed in couples whose in vitro fertilization was imparticable because of extreme sperm impairment. One thousand one hundred forty-seven mature oocytes were injected and 626 embryos were obtained., Results: In group 1, the pregnancy rate per embryo transfer and the implantation rate were respectively 22.7% and 12.3%. In group 2, the pregnancy rate per embryo transfer was 37.1% and the implantation rate was 17%. The statistical analysis of the embryos obtained in the two different groups did not demonstrate any difference in the distribution of the more regular and less fragmented embryos (group A) and those of the more irregular and fragmented embryos (group B). No statistical difference was demonstrated in the chronology of the division of these embryos (groups 1 and 2)., Conclusion: The pregnancy rate by cycle and by transfer reported by ICSI (p < 0.003 and p < 0.015 respectively) could be related to a significantly higher mean number of transferred embryos (2.65 vs 2.02) in probable relation with a higher cleavage rate (p < 0.00001).

In a series of 500 transfers of embryos obtained by in vitro fertilization, we examined the implantation rate of 1356 embryos transferred in utero. The average implantation rate per embryo was 15.1% and remained relatively constant, regardless of the number of transferred embryos per patient. The implantation rate per embryo, in relation to its morphology, was clearly lower when irregular blastomeres and fragments were present in the perivitelline area. Other embryos, regardless of their morphology, had an identical development potential. Analysis of the results of this series demonstrates the difficulty of determining the development potential of all the embryos on the basis of morphological criteria.

Embryo quality after IVF should allow provisions for their pregnancy potential. We have classified all the transferred embryos into 4 types according to morphological criteria and we have studied the implantation rate of the different types. The results show: That pregnancies have been obtained with the 4 types of embryos. That it has been impossible to demonstrate statistically significant differences between the different types of transferred embryos even if embryos morphologically normal seem to be more favourable than others to induce a pregnancy. That the average implantation rate for each transferred embryo is of 14.4%.