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 from 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 frozen-thawed embryos can be improved by removal of necrotic blastomeres before embryo transfer.