Preimplantation DNA Methylation Test (PIMT) in ART

The purpose of this clinical trial is to determine the safety and affect of DNA methylation level on ART. Subjects with blastocysts on day 5-7 of embryo culture will be biopsied. A Freeze-all strategy and a single frozen blastocyst transfer will be performed till all study-specific embryos have been transferred. Then whole genome bisulfate sequencing will be performed on all cells that obtained from biopsy. The investigators will perform whole genome DNA methylation sequence for two to seven blastocysts from one couple. The methylation level and genomic copy number variation will be analyzed by using the methylome data. Embryos with aneuploid chromosomes will be rejected for embryo transfer to uterus. The study will examine which kind of methylation level can produce the best clinical outcome for ART. Biopsied cells will perform with preimplnatation DNA methylation test (PIMT). DNA methylation level and chromosome copy number variation will be calculated by using whole genome DNA methylation sequencing data. As we do not kown which kind of methylation state can produce the best outcome in ART practice. This study will try to find a standard of selection embryos according to DNA methylation information. Under current stage, the selection of embryo is according to chromosome copy number. The embryo selection will not consider DNA methylation information for this study.