2025년 대한생식의학회(KSRM) 임상-3 A Comparative Study of Preimplantation Genetic Testing for Aneuploidy (PGT-A) Outcomes Based on the Degree of Blastocyst Expansion 배아 확장 정도에 따른 착상 전 유전검사(PGT-A) 결과 비교 분석

Min Ji Kim*, Seok Gi Kim, Ho Jeong Son, Ga Won Kim, Gyeong Deok Heo, Hye Yoon Kim, Ye Won Kim, Jae Hun Choi, Hye Kyung Noh, Ji Na Lee, Kyeong Ho Lee.
Mamapapa&baby Ob/Gyn Ulsan, Korea, Republic of South.

Objective

The known literature indicates that blastocysts with a higher cell number are associated with increased rates of euploidy, likely due to greater chromosomal stability and developmental competence. In reality, as blastocysts develop and expand, the cells within both the inner cell mass and the trophectoderm continue to divide, leading to an increase in the total cell number. Consequently, well-expanded blastocysts exhibit ongoing metabolic activity and cell proliferation.
The aim of this study was to investigate the relationship between the degree of blastocyst expansion and the outcomes of preimplantation genetic testing for aneuploidy (PGT-A), and to propose the optimal stage of blastocyst expansion for performing PGT-A.

Materials and Methods

In this study analyzed the PGT-A results of a total of 812 blastocysts, categorized into four groups based on the extent of expansion according to the Gardner grading system: Early (n=25), Expanding (n=239), Expanded (n=526), and Hatching (n=22) blastocysts. The euploid blastocyst rate was compared across the groups, and the correlation between the extent of blastocyst expansion and the euploid blastocyst rate was evaluated.

Results

The findings of this study indicate that performing PGT-A at higher stages of blastocyst expansion (Expanded and Hatching) may confer an advantage in acquiring euploid blastocysts compared to lower expansion stages. This advantage is likely due to the increased number of cells available for biopsy in more expanded blastocysts, thereby potentially enhancing the accuracy and diagnostic reliability of PGT-A.

Conclusions

The findings of this study suggest that the degree of blastocyst expansion can influence PGT-A results. Therefore, biopsying well-expanded blastocysts, rather than those with limited expansion, may help increase the probability of obtaining normal results from PGT-A.

한글요약

임신 성공률을 높이기 위해 배아의 발달과 착상전 유전자 검사(PGT-A)의 상관관계를 알아보고자, 본 연구에서는 총 812개의 배아를 대상으로 분석하였다. 그 결과, 초기 단계의 배아보다 '확장(Expanded)' 및 '부화(Hatching)' 단계까지 충분히 발달한 배아에서 유전적으로 정상일 확률이 높게 나타났다. 이는 세포 수가 많은 배아를 검사할수록 PGT-A의 진단 정확도와 신뢰도가 향상되기 때문이다. 따라서 잘 발달한 배아를 선택하여 유전 검사를 시행하는 것은 임신율을 높이는 데 기여할 수 있다.