ABSTRACT
The aim of the present study was to examine the effect of assisted hatching [AH] using zona-drilling techniques on pregnancy rate, miscarriage rate and multiple pregnancy rates, in a selected group of patients. Design: Aretrospective study. Setting: The Lister Hospital Assisted Conception Unit. Patients: Between July 1996 and December 2000, 141 patients were treated with AH prior to embryo transfer. The effect of AH was compared to a control group of 456 patients who underwent embryo transfer without AH during the same time period. Intervention: Assisted Hatching. Main outcome: Pregnancy rates, live births, single and multiple pregnancies and miscarriage rates. Patients who underwent AH were significantly older than the control group [37.23 +/- 4.47 vs 35.74 +/- 4.25 years: P = 0.001] and had significantly more previous cycles of failed IVF/ICSI [2.51 +/- 1.44 vs 2.02 +/- 5.72: P = 0.00]. The pregnancy rates, live birth rates, the incidence of single and multiple pregnancies and miscarriage rates were comparable in both groups. These results suggest that assisted hatching is not detrimental to health and may improve the outcome in patients with poor prognostic factors, resulting in rates of pregnancy comparable to that of the control group