P-167 The sperm parameters in doubling oocytes by the 1st polar body transfer technique: does it matter?
Authors: Ilyin I , Gontar J , Buderatska N , Lavrynenko S , Kazachkova N , Parnitska O , Herevich Y , Kapustin E , Lakhno Y 
Published: July 2024

Abstract

Study question
Does sperm parameters affect the effectiveness of the 1st polar body (PB) transfer in oocytes and embryo doubling?

Summary answer
Certain sperm conditions affect the transfer technique efficiency.

What is known already
Previous studies have shown the effectiveness of the 1st polar body (PB) transfer. The technique allows for the modification of donor oocytes to increase the number of cells suitable for fertilization and at the same time preserve the genetic relatedness to the patient. We established that the effectiveness depends on the morphology of the 1stPB. We also showed that the yield of high-quality blastocysts does not depend on whether fresh or thawed donor oocytes are used. But it is also important to understand whether sperm parameters have a significant effect on the performance of the technique.

Study design, size, duration
The study was performed in the Medical Center IGR from December 2017 to December 2023 and involved 93 patients (mean age 39.7±5.4 years) who underwent the 1st PB transfer and had indicated sperm parameters used for fertilization, including: normozoospermia (NS, n = 43), asthenozoospermia (AS, n = 24), asthenoteratozoospermia (ATS, n = 20), oligozoospermia (OS, n = 5), cryptozoospermia (CS, n = 1). We evaluated the pronuclear scoring, number of embryos on the 3rd and the 5th post-fertilization day, euploidy according to sperm conditions.

Participants/materials, setting, methods
We used donor oocytes, patients’ oocytes and their 1stPBs obtained from 93 women and their partners sperm with defined parameters in accordance with WHO norms for 2021. The procedure of donor oocyte enucleation and the 1stPBs transfers was carried out using Nikon Ti Eclipse(Japan) inverted microscope, Saturn 3 laser console(UK). Preimplantation genetic testing for aneuploidy was performed using trophectoderm biopsy. Samples were diagnosed using Ion S5(USA). Statistical analysis was carried out using Chi-square test.

Main results and the role of chance
The total number of donor oocytes modified by the 1stPB of patient’ oocytes was 364, which were distributed as follows by sperm status: NS - 159 oocytes, AS - 103 oocytes, ATS - 77 oocytes, OS - 19 oocytes, and CS - 6 oocytes. The mean age of the female patients according to the groups was similar (39.6±4.9, 39.8±6.2, 40.0±3.8, 37.8±6.1,40, respectively). The number of 2PN pattern during pronuclear scoring was distributed among groups (NS:AS:ATS:OS:CS) with the following percentages 69.2:65.1:62.3:73.7:66.7, respectively. Among the developing embryos on the 3rdday the distribution was 46.6:46.5:36.4:57.9, respectively. No viable embryos were formed in the CS group, so the group was not included in further calculations. Statistically significant difference (SSD) was not found between the groups on the above-mentioned stages of development (p0.05). On the 5thday the number of developing embryos (percents) was distributed as follows: 23.3:28.2:11.7:31.6 for NS:AS:ATS:OS, respectively. It is worth noting that SSD was found between NS and ATS, OS and ATS groups (p &lt; 0.05) and AS and ATS groups (p &lt; 0.001). Percentage of euploid embryos relative to the number of examined blastocysts from groups NS:AS:ATS was 30.8:23.1:22.2, respectively, SSD wasn’t found between the groups(p &gt; 0.05).

Limitations, reasons for caution
To increase performance of the 1st PB transfer technique it is also worth considering such parameters as sperm DNA fragmentation and level of sperm oxidative stress, which reflect the chromatin state of the male gamete.

Wider implications of the findings
The study showed that among patients with asthenoteratozoospermia, the yield of viable embryos was significantly lower compared to the other sperm conditions studied. This fact must be taken into account when predicting the result of using the 1st PB transfer technique.

Trial registration number
N/A