Clinical application of a new assisted hatching method using a piezo-micromanipulator for morphologically low-quality embryos in poor-prognosis infertile patients

Objective: To assess the effect of a assisted hatching technique using a piezo-micromanipulator on pregnancy rates in poor-prognosis infertile patients. Design: A prospective randomized study. Setting: The Infertility and IVF unit of the Kyoto University Hospital. Patient(s): Infertile patients who had been treated for >4 years and failed in previous IVF trials at least twice. Intervention(s): Two hundred forty-eight IVF cycles from 173 patients were divided into two groups: cycles with the transfer of embryos treated by assisted hatching and cycles with the transfer of nontreated embryos. Each group was subdivided into two groups according to embryo morphology: cycles in which three or two morphologically good-quality embryos were transferred and cycles in which one or no morphologically good-quality embryos were transferred. Assisted hatching was performed by a piezo-micromanipulator. Main Outcome Measure(s): The clinical pregnancy rates and implantation rates. Result(s): The clinical pregnancy and implantation rates were significantly higher in the assisted hatching group of patients with three or two good-quality embryos than in the other three groups. Conclusion(s): The assisted hatching using a piezo-micromanipulator improved the pregnancy and implantation rates in poor-prognosis infertile patients with good-quality embryo transfer but had no effect in patients with low-quality embryo transfer. (Fertil Sterilo 1999;71:1014-8. (C) 1999 by American Society for Reproductive Medicine.).