Received April 20, 2011
Accepted May 02, 2011

Objective: To assess the impact of assisted hatching on the results of in vitro fertilization in women older than 35 years. Methods: 232 cycles of in vitro fertilization in patients older than 35 years old were retrospectively evaluated. The patients were divided in 2 groups: assisted hatching group and control group. Results: The mean age was similar in both groups (38±2,12 and 37,86± 2,17, assisted hatching group and the control group, respectively, P = 0,58). When compared to the control group, the patients who had done assisted hatching showed significantly less oocytes retrieved and metaphase II oocytes, and worse fertilization rate (74% x 82%, P=0,016) and embryo freezing rate (19% x 35%, P = 0,007). Besides this, the patients treated with assisted hatching had already done significantly more previous IVF cycles, and used more ampoules of gonadotropins. There were no statistical differences in implantation (18% x 20%) and pregnancy rates (37% x 41%) between both groups. Conclusions: the patients who had the “assisted hatching” showed characteristics relating to the cycle of IVF indicating a worse prognosis for pregnancy, but even so, they obtained an implantation and pregnancy rate similar to the control group patients.