Thesis (Ph.D.) - Cairo University - National Institute of Laser Enhanced Sciences - Department of Laser Application in Medical and Biological

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 rates 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. 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 LAH group to induce zonal microdissection. The quality and safety of the embryos are assisted morphologically after hatching and also by measuring malondialdehyde before and after application of laser to determine if laser might be a source of oxidative stress, which affects embryos quality, implantation rates and pregnancy rates

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