Abundance of cell-free mitochondrial DNA in spent culture medium associated with morphokinetics and blastocyst collapse of expanded blastocysts

Abstract

Purpose: This retrospective observational study investigated relationships between the abundance of cell-free mitochondrial DNA (cf-mtDNA) in spent culture medium (SCM) of human-expanded blastocysts and their morphokinetics to address the question of whether the abundance of cf-mtDNA in SCM could predict the quality of blastocysts.

Methods: Embryos (n = 53) were individually cultured in a time-lapse incubator until they reached the expanded blastocyst stage (5 or 6 days), following which copy numbers of cf-mtDNA in SCM (20 μL) of expanded blastocysts were determined using real-time PCR.

Results: The duration between start of blastulation to expanded blastocyst (tEB-tSB) and between that of the blastocyst stage to expanded blastocyst (tEB-tB) significantly and positively correlated with the abundance of cf-mtDNA in the SCM (tEB-tSB: r = .46; P < .01; tEB-tB: r = .47; P < .01). The abundance of cf-mtDNA in the SCM was significantly greater in blastocysts with blastocyst collapse (BC), than without BC, and significantly and positively correlated with the number of BC.

Conclusions: The abundance of cf-mtDNA in the SCM was associated with expansion duration and BC. Thus, cf-mtDNA abundance in the SCM serves as a marker to predict the quality of expanded blastocysts.

Keywords: blastocyst collapse; cell‐free DNA; embryo selection; mitochondria; time‐lapse incubator.