Prospective randomized trial on the use of laser assisted hatching for transfer of frozen/thawed embryos in human Intracytoplasmic Sperm injection

Abstract

Background: Cryopreservation of human embryos has become an essential part of assisted reproduction, however it might be associated with zonal hardening, which could reduce implantation rate and clinical pregnancy rates. Assisted hatching has been used to induce microdissection of the zona pellucida. Many techniques have been used, such as mechanical, chemical, piezo and laser techniques. Objective: To determine if laser assisted hatching improves both the implantation and clinical pregnancy rates in women using transferred frozen/thawed embryos. Study design: Prospective randomized study. Patients and methods: 160 women, scheduled for transfer of cryopreserved embryos, were randomized in two equal groups using sealed envelopes; a laser assisted hatching group (test group), and a control group, each included 80 women. On the day of embryo transfer, Diode laser was used in test group to induce zonal microdissection, the quality and safety of embryos is assessed morphologically after hatching. On the other hand, the zona of the control group were left intact. Both implantation and clinical pregnancy rates were estimated. Results: Laser assisted hatching group had implantation rates and clinical pregnancy of 50% and 37.5% respectively. Non laser assisted hatching group had lower implantation rates and clinical pregnancy; 47.27% (P value = 0.87) and 27.5% (P value = 0.237) respectively. Conclusion: Laser assisted hatching seems to improve both the clinical pregnancy and implantation rates amongst patients using frozen/thawed embryos, however that was statistically insignificant.

Keywords

• Laser assisted hatching
• Cryopreservation
• Zona pellucida
• Implantation rate and pregnancy rate