Evaluate the risk in conventional IVF frozen human blastocysts undergoing PGT using a new quantification method for parental contamination testing (qPCT)

Objective To establish a method to assess risks associated with preimplantation genetic testing (PGT) in embryos simultaneously with adhered sperm and cumulus cells. Design A prospective pilot study. Setting University teaching hospital. Patient(s) 120 frozen blastocysts that could be biopsied from 34 patients who had experienced repeated implantation failure or abortion due to chromosomal abnormalities after embryos transfer in prior routine IVF cycles. Intervention(s) Chromosome screening and parental DNA contamination testing was performed in the surplus frozen IVF blastocysts from 34 patients. Main Outcome Measure(s) Parental DNA contamination rate and euploidy rate in biopsied blastocysts. Result(s) A new quantification method for parental contamination testing (qPCT) in single-cell whole-genome amplification (WGA) products based on allelic ratio analysis was established and validated in an artificial model by comparing 22 results obtained before and after adding different numbers of sperm and cumulus cells to biopsied TE cells. The results of the prospective clinical study of qPCT-PGT-A showed that the maternal contamination rate was 0.83% (1/120) and the risk of paternal contamination was negligible. The euploidy rate in these blastocysts was 47.50% (57/120), and 21 frozen embryo transfer (FET) cycles resulted in ten ongoing clinical pregnancies and four healthy births. Conclusion(s) The evidence we provide in the study shows a low risk of PGT in embryos simultaneously with adhered sperm and cumulus cells. The qPCT assay can be used to detect the risk of potential contamination and ensure the accuracy of PGT results, thereby improving the clinical outcome of IVF. Capsule During PGT for human frozen conventional IVF embryos, paternal source pollution is negligible, while maternal pollution can not be ignored. qPCT method can effectively detect the parent DNA contamination in WGA products of biopsied TE cells.