Laser-assisted removal of necrotic blastomeres from cryopreserved embryos that were partially damaged

Objective: To examine whether the developmental potential of embryos that were partially damaged after freezing and thawing can be improved by removal of necrotic blastomeres before embryo transfer. Design: Prospective pilot study and observational clinical series. Setting: Private hospital. Patient(s): Two hundred thirty-five infertile Couples undergoing frozen embryo transfer. Intervention(s): Removal of necrotic blastomeres from frozen-thawed human embryos. Main Outcome Measure(s): Pregnancy and implantation rates. Result(s): Removal of necrotic blastomeres front partially damaged frozen-thawed embryos before transfer increased rates of pregnancy (45.7% vs. 17.1%). ongoing pregnancy (40.0% vs. 11.4%) and ongoing implantation (16.2% vs. 4.3%) compared with the control group, in which necrotic blastomeres were not removed. A similarly high implantation rate (16.7%) was seen a Subsequent clinical series in which necrotic blastomeres were removed from all partially damaged embryos. Conclusion(s): The viability of partially damaged froze with awed embryos can be improved by removal of necrotic blastomeres before embryo transfer. (C) 2002 by American Society for Reproductive Medicine.