A comparison of post-thaw results between cryopreserved embryos derived from intracytoplasmic sperm injection and those from conventional IVF

Objective: To study the effect of freezing on early stage embryos derived f rom intracytoplasmic sperm injection (ICSI) or from IVF. Design: Prospective, controlled clinical study. Setting: Private IVF center. Patient(s): Sixty-seven consecutive patients undergoing frozen-thawed embry o transfer cycles. Intervention(s): Early stage embryos were frozen, thawed, and transferred. Main Outcome Measure(s): Post-thaw survival, implantation and pregnancy rat es. Result(s): We noted an 88% post-thaw survival rate, an 18% implantation rate, and a 52% pregnancy rate in the ICSI group and 81%, 11%, and 25%, re spectively, with conventional fertilization. Conclusion(s): Early stage embryos (either zygote or 2-4 cells) derived fro m ICSI can he frozen with confidence and higher post-thaw survival and preg nancy rates can be achieved when compared with those from conventional IVF. ((C)1999 by American Society for Reproductive Medicine.).