A randomized double-blind controlled study on the efficacy of laser zona pellucida thinning on live birth rates in cases of advanced female age.

BACKGROUND It is conceivable that defective embryo hatching plays a part in the mechanisms involved in the decrease of embryo implantation rates with advancing age. In an effort to test this hypothesis, we tested the effectiveness of assisted hatching (AH) in women > or =37 years of age. METHODS We prospectively studied 103 IVF-embryo transfer patients undergoing 103 embryo transfers. All of them were > or =37 years of age and had <3 previous IVF-embryo transfer attempts. Laser-AH of transferred embryos was either performed (AH group, n = 49) or not (control group, n = 54) according to randomized and double-blind methodology. Primary outcome was live birth rate. RESULTS Population characteristics were comparable in AH and control groups as well as the mean number of embryos transferred (2.7 +/- 0.6 versus 2.7 +/- 0.6) and the prevalence of top quality embryos transferred (65 versus 59%, respectively). We failed to find any statistically significant difference between AH and control groups with regard to implantation (16.1 versus 16.7%, respectively) and live birth rates (22.4 versus 29.6%, respectively). CONCLUSION The present study indicates that AH does not improve IVF-embryo transfer outcome in women aged > or =37 years.