CELL-FREE DNA IN SPENT EMBRYO CULTURE MEDIUM AND ITS APPLICATION IN NON-INVASIVE PREIMPLANTATION GENETIC TESTING: A REVIEW

Abstract

To elucidate the factors that influence the concentration and quality of cell‑free DNA (cfDNA) in spent embryo culture medium (SECM) and to assess the potential application of cfDNA in non‑invasive preimplantation genetic testing (niPGT). Methods: A narrative review was conducted of studies on cfDNA in SECM and niPGT retrieved from major biomedical databases, selecting articles that described the origin, characteristics and determinants of cfDNA during embryo culture, as well as sample collection and processing procedures. Results: Multiple studies have reported moderate to high concordance between niPGT results based on cfDNA in SECM and those from trophectoderm biopsy; however, reliability and reproducibility remain limited, with wide variation in concordance rates across studies. Key influencing factors include culture conditions and duration, type and volume of culture medium, timing and method of sample collection, the extent of maternal or laboratory DNA contamination, and the protocols used for cfDNA processing, amplification and sequencing. Conclusion: Identifying and controlling these factors is essential for standardizing protocols for embryo culture, SECM collection and analysis, thereby improving the accuracy of niPGT and facilitating its broader clinical implementation in assisted reproductive practice.