A comparison between quarter, partial and total laser assisted hatching inselected infertility patients

BACKGROUND: The object of this study was to evaluate the efficacy of laser assisted hatching (LAH) of embryos on implantation and pregnancy rates of a selected group of infertility patients. METHODS: A total of 322 cycles usi ng LAH was undertaken in our Centre between June 1998 and September 1999. P atients were offered LAH if they fell in either one or more of the followin g categories: (i) Patients over 37 years of age undergoing either IVF or in tracytoplasmic sperm injection (ICSI) treatment cycles; (ii) patients with more than 2 previous treatment cycle failures; (iii) patients undergoing fr ozen embryo replacement cycles and (iv) women who were considered to be poo r responders. The initial results of totally breaching the zona pellucida ( total LAH; group 1) did not meet with our expectations. We subsequently mod ified the technique to thinning one area of the zona pellucida (partial LAH ; group 2) and this thinned area was then extended to a quarter segment (qu arter LAH; group 3). RESULTS: In group 1, the pregnancy rate was 14.6% with a clinical pregnancy rate of 5.2%. In group 2 the pregnancy rate was 20.9% with a clinical pregnancy rate of 18% and for patients in group 3 the preg nancy rate was 29.0% with a clinical pregnancy rate of 22.1%. CONCLUSIONS: Overall there was firm statistical evidence that the pregnancy and clinical pregnancy rates arising from quarter LAH were higher in comparison with pa rtial and total LAH.