P-180 Trophectoderm biopsy technique and its effect on life birth rates: a prospective study
Authors: Montalvo V , Pino J , Garcia-Faura A , Garcia F , Munuera A , Paricio A , Trigas R , Marques B 
Published: July 2024

Abstract

Study question
Do life birth rates of euploid embryos vary based on factors such as laser intensity, number of laser shots, and the biopsy technique employed?

Summary answer
This study found no correlation between biopsy technique parameters and life birth rates of euploid embryos, underscoring the robustness of current trophectoderm biopsy methods.

What is known already
Embryo biopsy for Preimplantation Genetic Testing (PGT) must achieve two primary objectives: ensuring that the biopsied material accurately reflects the genetic makeup of the embryo and maintaining the viability of the embryo without compromise. The strategy that most closely aligns with accomplishing these dual goals is trophectoderm (TE) biopsy. However, it’s important to note that there is currently no standardized TE biopsy procedure, leading to the coexistence several techniques. Given the potential impact of TE biopsy on trophectoderm quality and integrity, and consequently on implantation, there is a critical need for studies to assess the effects of different biopsy techniques.

Study design, size, duration
This prospective observational study spanned from 2019 to 2021 and involved 298 Preimplantation Genetic Testing for Aneuploidy (PGT-A) treatments, incorporating a total of 1187 trophectoderm (TE) biopsies. Embriologyst were trained in both Pulling and Flicking techniques and choose between the two techniques according to their criteria. Pulling involved laser pulses weakening junctions, facilitating TE detachment with moderate tension. Flicking substituted tension with a cutting motion between holding and biopsy pipettes.

Participants/materials, setting, methods
Biopsy technique (pulling/flicking), number of laser shots (1-10), laser intensity (200µs-600µs), and the embriologyst responsible for the biopsy were annotated for every biopsied embryo. PGT indication, stimulation protocol, patient age (39.32±4.22), embryo quality, and sperm diagnosis were annotated and used as possible confounding factors in a logistic regression model to understand the impact of each independent variable on the log-odds of the outcome.

Main results and the role of chance
The 1187 trophectoderm biopsies resulted in a total of 410 (34.5%) euploid embryos. Among these, 237 euploid embryos underwent individual transfers, with 153 subjected to Pulling technique and 84 to Flicking technique leading to a total of 120 healthy babies (50.6% life birth rate).
Logistic regression, considering potential confounding factors failed to identify any variable significantly influencing the likelihood of life births (p &lt; 0.05). Both Pulling and Flicking techniques demonstrated comparable success rates (52.9% vs 46.4%), with no discernible impact from variations in laser shots (1-3=65.0%; 4-6=45.6%; &gt;6=66.7%) or intensity (200µs=75.0%; 300µs=45.0%; 400µs=50.6%; 500µs=50.94%; 600µs=50.0%).
Furthermore, when evaluating the embryologist conducting the biopsy, no significant differences were identified among operators (p &lt; 0.05). This pattern persists for miscarriage rates, indicating no influence from biopsy technique, laser shots, or laser intensity (p &lt; 0.05). Thus, our findings underscore that variations in trophectoderm biopsy variables, when performed by an experienced embryologist, do not adversely impact trophectoderm quality and do not compromise success rates.

Limitations, reasons for caution
This is a single-center, observational study, conducted from 2019 to 2021, and this may limit generalizability. The sample size variation between biopsy techniques and potential unmeasured confounders pose challenges. The assumption of technique homogeneity, and reliance on binary outcomes underscore caution in interpreting findings.

Wider implications of the findings
The lack of correlation between biopsy parameters and life birth rates in our study underscores the effectiveness and reliability of current biopsy techniques. This discovery offers reassurance regarding the proficiency of trophectoderm biopsy methods for achieving success in IVF treatments.

Trial registration number
Not Applicable