Effect of time post warming to embryo transfer on human blastocyst metabolism and pregnancy outcome.

Purpose: This study is aiming to test whether variation in post warming culture time impacts blastocyst metabolism or pregnancy outcome.

Methods: In this single center retrospective cohort study, outcomes of 11,520 single frozen embryo transfer (FET) cycles were analyzed from January 2015 to December 2020. Patient treatments included both natural and programmed cycles.

Fluorescence lifetime imaging microscopy (FLIM) detects differences in metabolic signatures between euploid and aneuploid human blastocysts.

Study Question: Can non-invasive imaging with fluorescence lifetime imaging microscopy (FLIM) detect metabolic differences in euploid versus aneuploid human blastocysts?

Summary Answer: FLIM has identified significant metabolic differences between euploid and aneuploid blastocysts.

What Is Known Already: Prior studies have demonstrated that FLIM can detect metabolic differences in mouse oocytes and embryos and in discarded human blastocysts.

Study Design, Size, Duration: This was a prospective observational study from August 2019 to February 2020.

Metabolic state of human blastocysts measured by fluorescence lifetime imaging microscopy.

Study Question: Can non-invasive metabolic imaging via fluorescence lifetime imaging microscopy (FLIM) detect variations in metabolic profiles between discarded human blastocysts?

Summary Answer: FLIM revealed extensive variations in the metabolic state of discarded human blastocysts associated with blastocyst development over 36 h, the day after fertilization and blastocyst developmental stage, as well as metabolic heterogeneity within individual blastocysts.

What Is Known Already: Mammalian embryos undergo large changes in metabolism over the course of preimplantation development. Embryo metabolism has long been linked to embryo viability, suggesting its potential utility in ART to aid in selecting high quality embryos.