The purpose of this study is to determine if slush nitrogen for embryo vitrification results in higher sustained implantation rates compared to the conventional use of liquid nitrogen. Routine ovarian stimulation, oocyte retrieval and embryology care will ensue. All blastocyst stage embryos will be randomized to either the control (liquid nitrogen) or intervention group (slush nitrogen) and vitrified after trophectoderm biopsy has been performed for PGT-A (preimplantation genetic testing for aneuploidy). A single, chromosomally normal embryo will be transferred in a subsequent frozen embryo transfer cycle per routine. Implantation rates and pregnancy outcomes will be assessed.
The proposed study is a single-blind randomized controlled trial which seeks to characterize implantation rates following embryo vitrification and subsequent warming with both slush nitrogen and liquid nitrogen. After warming, implantation rates and pregnancy outcomes will be assessed.