Higher Implantation Rate Using Modified Quarter Laser-Assisted Zona Thinning in Repeated Implantation Failure

Background/Aims: Some embryo implantation problems in patients with recurrent implantation failure may be explained by the inability of the embryo to hatch out of its zona pellucida. In this case-control study, a study group which had received modified quarter laser-assisted zona thinning (mQLAZT) was compared with a control group which had not received mQLAZT with respect to reproductive outcome. Methods: Cycles from patients with a 4th fresh embryo transfer (ET) after 3 previously failed ET cycles (no β-hCG detected) were included. Cases (group A, n = 53) included ET cycles from patients who received a 4th ET with fresh embryos after mQLAZT. Controls (group B, n = 86) included ET cycles from patients who had a 4th ET without mQLAZT. The clinical implantation rate and live birth rate per embryo transferred were measured. Results: The clinical implantation rate with positive fetal heart beat per embryo transferred was significantly higher (p = 0.035) in group A (22/107 or 21%) than in group B (18/166 or 11%). Conclusion: The data of this case-control study suggest that mQLAZT can be effective in the treatment of patients with recurrent implantation failure, but need to be confirmed by randomized trials.