P-135 Impact of TE-biopsy practitioners on PGT-A results and live-birth outcomes after single euploid blastocyst transfer: comparison of 19 TE-biopsy practitioners in a single center
Authors: Ueno S , Kuroda T , Aoyama N , Okimura T , Kato K 
Published: July 2024

Abstract

Study question
Can TE-biopsy practitioners impact pre-implantation genetic test for aneuploidy (PGT-A) results, pregnancy, and live-birth outcomes in a single center that has nineteen biopsy practitioners?

Summary answer
Yes. Trophectoderm (TE)-biopsy practitioners, especially micromanipulation experience, can impact PGT-A results but do not impact pregnancy or live-birth outcomes after single euploid blastocyst transfer (SeBT).

What is known already
Recently, PGT-A has become important in in vitro fertilization treatment. However, several factors can impact the accuracy and interpretation of PGT-A results. Several studies have suggested that TE-biopsy practitioners can impact PGT-A results. However, these findings are controversial because these previous studies used data from a low number of TE-biopsy practitioners and from multiple centers. There is, therefore, still limited knowledge of the impact of TE-biopsy practitioners on PGT-A results and their clinical outcomes.

Study design, size, duration
A total of 3,589 PGT-A cycles (average maternal age, 40.9±3.2; 1,168 patients; February 2020 to November 2022) were retrospectively analyzed. Furthermore, 779 single frozen euploid blastocyst transfer (SeBT) cycles were analyzed. First, we investigated the association between TE-biopsy practitioners and transferable blastocysts that included euploid and low-level mosaic blastocysts (LLM, 20 to 40% abnormal cells). Second, we analyzed the impact of TE-biopsy practitioners on pregnancy and live-birth outcomes after SeBT.

Participants/materials, setting, methods
The nineteen practitioners (Years of intracytoplasmic sperm injection (ICSI) experience: 2 to 20 years) who received the same training performed a total of 5,613 TE-biopsies for PGT-A. The same practitioner performed both the biopsy and the tubing procedures for each blastocyst they biopsied. The Wald test for multivariable logistic regression analysis (mLR) was used to determine the impact of TE-biopsy practitioners. The confounding factors were selected by univariable logistic regression analysis before mLR.

Main results and the role of chance
TE-biopsy was carried out by the flicking method with laser assistance and it was taken five to seven TE cells. Overall, 22.9% of blastocysts were transferable blastocysts (euploid: 21.1%, LLM: 1.8%). The results were inconclusive for 0.1% of the blastocysts. Maternal/paternal age, number of previous egg retrieval/embryo transfers, anti-Müllerian hormone, sperm characteristics, indication for PGT-A, number of previous deliveries/chemical abortions, blastocyst quality (the day of vitrification, inner diameters of blastocysts, and Gardner grading) were used as confounding factors on the mLR. TE-biopsy practitioners were significantly associated with both ensuring transferable blastocysts and LLM in transferable blastocysts (p &lt; 0.05). Additionally, the practitioner characteristics that impact ensuring transferable blastocysts or LLM in transferable blastocysts were assessed in a sub-analysis. Years of ICSI experience (p &lt; 0.05), number of ICSI performed during the last years (p &lt; 0.05), and number of TE-biopsies at that point (p &lt; 0.05) were associated with ensuring transferable blastocysts and LLM in transferable blastocysts. On the other hand, TE-biopsy practitioners did not have a significant impact on biological pregnancy, chemical abortion, pregnancy, or live-birth rates after SeBT.

Limitations, reasons for caution
This study did not determine the influence of TE biopsy itself and the laser assistance on PGT-A and clinical results. And this study was based on a minimal stimulation cycle. Moreover, the patient cohort in this study only included cases involving recurrent implantation failure or repeated pregnancy loss.

Wider implications of the findings
This study showed that TE-biopsy practitioners could impact decreasing transferable blastocysts, and this depends on their micromanipulation experience. This result suggests TE-biopsy training should be started when embryologists have gained several years of experience with ICSI procedures. This could prevent the decline in the efficacy of PGT-A for clinical results.

Trial registration number
not applicable