Assisted hatching increases the implantation and pregnancy rate of in vitro fertilization (IVF)-embryo transfer (ET), but not that of IVF-tubal ET in patients with repeated IVF failures

Objective: To assess the effect of augmenting IVF with assisted hatching in the treatment of patients with repeated IVF failures. Design: Prospective randomized study. Setting: Division of Reproductive Endocrinology and Infertility of National Taiwan University Hospital. Patient(s): From July 1993 to February 1996, 49 patients with repeatedly failed IVF were treated with assisted hatching and were compared with 51 control subjects without assisted hatching. Intervention(s): Assisted hatching. Main Outcome Measure(s): Pregnancy rate and implantation rate per embryo after IVF-ET or IVF-tubal ET (TET) were measured. Result(s): The pregnancy rate (PR) in the assisted hatching group was found to be 36.7% compared with 19.6% in the control group, but the difference was not significant. When only patients receiving IVF-ET were considered, it was observed that the PR was significantly higher in the assisted hatching group than the control group (42.4% versus 16.1%). With IVF-TET however, the PR was found to be similar in both assisted hatching and control groups (25.0% and 25.0%, respectively). The rate of embryonic implantation in the IVF-ET patients was 11.0%, which was significantly higher than that of control embryos (3.%). Conclusion(s): These results implied that IVF-ET, combined with assisted hatching, may improve the PR and implantation rate in patients with repeated IVF failures, but the same was not true in the case of IVF-TET.