[Reinsemination of oocytes by intracytoplasmic sperm injection after the failure of conventional fertilization. Early embryonal development].

OBJECTIVE

To analyze the influence of intracytoplasmic sperm injection (ICSI) on early embryo development used for reinsemination of unfertilized 1-day-old oocytes.

DESIGN

Prospective observational study.

MATERIALS AND METHODS

A total of 126 embryos resulted from reinsemination by ICSI were analyzed with regard for the time course of cleavage and the quality of embryos at 48 hours after injection. Results were compared with those obtained in 698 embryos obtained after routine ICSI program.

RESULTS

It has been shown that embryos derived from reinsemination developed slower in comparison with those obtained after regular ICSI program. At 48 hours after microinjection 50% of embryos achieved 4 blastomeres stage and 37% remained on 2 cells stage. 71% of regular ICSI embryos at this same time showed 4 blastomere or more, only 16% remained on 2 blastomeres stage. The quality of embryos was similar in two compared groups, however those obtained following reinsemination at 4 blastomere stage were significantly poorer quality.

CONCLUSION

Embryos derived from reinsemination of 1-day old oocytes unfertilized after conventional IVF developed slower and the quality of embryos at 4 blastomere stage was poorer comparing to regular ICSI embryos.