P-230 Does laser-assisted hatching improve pregnancy rates : a retrospective analysis

Abstract

Abstract Study question Is there any effect of laser-assisted zona drilling in improving pregnancy outcomes in women undergoing vitrified-warmed embryo transfers? Summary answer Our data suggests that there is evidence of possible improvement in pregnancy rates with laser-assisted hatching of embryos among women >40 years of age. What is known already Mammalian embryo is surrounded by a glycoprotein shell called zona pellucida. The embryo must hatch out of this shell for it to implant in the uterus. However, certain factors such as sub-optimal in vitro culture conditions, advanced maternal age, zona-hardening due to vitrification and warming, among others, negatively impact the ability of the embryo to escape from the matrix surrounding it. Laser-assisted hatching is the safest and easiest technique available to overcome the problem of hatching by artificially disrupting the zona, though there isn’t sufficient data available on whether this has any actual benefit or is just a fancy add-on. Study design, size, duration Retrospective cohort study comparing embryo transfer results of 88 women whose embryos underwent LAH prior to transfer with that of a control group of women. Data was collected from embryo transfers that took place between March 2021 to December 2022. Participants/materials, setting, methods Beta-hCG results of women (N = 88) whose embryos underwent LAH prior to transfer was compared with the results of transfer without LAH in women (N = 88) of similar age and clinical history. Patient age, clinical indications and embryo grades were comparable across both groups. LAH was performed immediately post-warming of blastocysts using a 1.48 µm diode to drill the zona at a point opposite the ICM. Data was analyzed using independent t test and chi square test. Main results and the role of chance Women from both test and control groups were further stratified into the following sub-groups based on age – A (25-29 years), B (30-34 years), C (35-39) and D ( >40 years). Beta-hCG results were assessed and was found to be lower in sub-groups A (57.1% vs. 78.5%) and B (46.4% vs. 67.7%) of the test group as compared to control. It was marginally higher in test group C as compared to that of control (50% vs. 47.3%). However, we found an increase in pregnancy outcomes of test sub-group D in comparison to control (83.3% vs. 20%). Limitations, reasons for caution This is a retrospective, preliminary study to assess initial results of effect of LAH on vitrified-warmed embryo transfer outcomes. A prospective study with a larger sample size is needed to confirm our results in both frozen and fresh embryos. Wider implications of the findings Our results indicate that laser-assisted hatching does not provide any advantage except possibly in older women above the age of 40 years. Thus we can select the exact group of patients who would benefit with this add-on and offer it to them routinely to improve their pregnancy rates. Trial registration number Not applicable