Study to improving embryo yield pregnancy on the effect of assisted hatching (lah) in vitro fertilization

Laser assisted hatching (LAH) technique is based on the hypothesis that making an artificial hole on zona pellucida (ZP) can help embryo to easily hatching out of ZP. This technique has been shown to increase implantation and pregnancy rates in women of advanced age, in women with recurrent implantation failure and following the transfer of frozen–thawed embryos. Assisted hatching (AH) by mechanical, chemical, or laser manipulation is applied to enable implantation in situations where it is decreased, such as, aging, high level of basal FSH, zona hardening, or in all ART treatments were implantation fail on two previous attempts. Zona assisted hatching was introduced to overcome the zona barrier in instances of suspected impairment to zona hatching due to either zona hardening or thickness, particularly in patients with repeated failures.This study aimed to assess the effect of LAH in both fresh and frozen thawed embryos before to be transferred into a recipient uterus. Within a 18-month period a total of 220 embryo transfer cycles (110 LAH and 110 control) were performed using fresh embryos (fresh transfer) and 220 embryo transfer cycles (110 LAH and 110 control) using frozen-thawed embryos (frozen-transfer). The mean of embryos transferred in each cycle was 2.6±1.6 in fresh-transfer and 2.4±1.2 in thawed-transfer cycles. Implantation rate in fresh-transfer cycles was 41.8% vs 23.6% respectively in LAH and control groups. In frozen-transfer cycle, implantation rate in the LAH group was 50.98 % and in the control group 38.1%. The rate of clinical pregnancies in fresh-transfer was 34.5% vs 18.1% in LAH and control respectively, while in the thawed-transfer was 40.9% in LAH and 30.9% in control. The percentage of early miscarriages related to biochemical pregnancies in fresh-transfer cycles was 10.5% in LAH and 10% in control while and in frozen-thawed cycles the percentage of early miscarriages related to clinical pregnancies was; 8.89% and 8.82% respectively in LAH and control groups. This result was equal or higher than other researchs about embryos transfer with or without LAH and we conclude that LAH improves outcome of fresh or frozen-thawed embryo transfer practices.