Is assisted hatching beneficial in patients with recurrent implantation failures?

Purpose: To assess the possible role of assisted hatching in patients with recurrent implantation failure during IVF cycles. Design: Prospective randomized study. Setting: IVF unit of an academic medical center. Patients: Women who underwent IVF after at least three failed IVF-ET attempts. Interventions: Patients were prospectively randomized to undergo assisted hatching of their embryos prior to their replacement by mechanical partial zona dissection. Results: The study (assisted hatching) and control groups included 104 and 103 patients, respectively. There were no significant between-group differences in patient age, cause of infertility, mean number of previous IVF trials, number of oocytes retrieved, fertilization rate, or number of embryos transferred. No difference in pregnancy rate was noted on comparison of the whole study group, to the whole control group (21% and 27%, respectively). However, when the results were re-analyzed by age groups, assisted hatching was found to be harmful in the youngest group (< 34 years), significantly decreasing pregnancy rates (15% vs 35%, p < 0.05). Conclusion: Repeated implantation failure alone is not an indication for assisted hatching. Although assisted hatching appears to be effective in a selected group of older patients, in younger patients it may further hamper implantation and should be avoided.