Prospective International Multi-center Clinical Trial of PGT-A Upgrade

Overview

The goals of this international multicenter cross-sectional study are: 1. To provide patients with a comprehensive PGT solution capable of simultaneously detecting embryonic chromosomal aneuploidy, mosaicism, microdeletions/ microduplications, heteroploidy, and heterozygosity (LOH) in a single assay, thereby reducing miscarriage and birth defects; 2. To perform PGT analysis on abnormally fertilized embryos, select euploid embryos with normal ploidy, and calculate embryo utilization rates; 3. To reduce the false-positive rate through confirmation of mosaic embryos and subsequent analysis of its origin, thereby minimizing embryo wastage; 4. To provide molecular genetic evidence for expert consensus on clinical management of atypically fertilized embryos, of pathogenic/likely pathogenic small CNVs, optimize mosaic embryo transfer strategies, and inform preconception intervention; 5. To enhance international PGT testing standards through international multi-center collaboration. The study will enroll patients undergoing PGT-A from seven domestic and international centers, with patient enrollment expected to be completed within one year. PGT-A upgrade testing will be performed on embryos from enrolled patients, and the incidence rates of Incidence of microdeletions/microduplications, heteroploidy, LOH will be statistically analyzed. All patients who undergo embryo transfer will be followed up for clinical outcomes and birth defects.

The study will enroll 6,694 embryos derived from typical fertilization (2PN) that meet the inclusion and exclusion criteria in patients undergoing PGT-A, as well as all embryos derived from atypical fertilization (0PN/1PN/3PN). In contrast to conventional PGT-A testing, PGT-A upgrade testing will be performed on the embryos to comprehensively analyze multiple embryonic abnormalities in a single detection, including aneuploidy, mosaicism, microdeletion/microduplication, heteroploidy, and loss of heterozygosity (LOH), and to calculate their respective incidence rates. In addition to embryos derived from 2PN, embryos from 0PN/1PN/3PN will also be cultured to the blastocyst stage for trophectoderm (TE) cell biopsy. Euploid embryos identified by PGT-A upgrade testing will be recorded, and the utilization rate of atypically fertilized embryos will be evaluated. For mosaic embryos, a previously established parental haplotype origin algorithm will be applied to distinguish true versus false mosaicism and identify the origin of abnormalities, thereby recognizing "false-positive" mosaic embryos and further increasing the number of transferable embryos. Patients will receive euploid embryo transfer (from 2PN) in accordance with routine clinical practice. In cases where no 2PN-derived euploid embryos are available, transfer of 0PN/1PN/3PN-derived euploid embryos and embryos classified as "false-positive" mosaic may be considered after the patient has been fully informed of the risks and provided informed consent. All transfer cycles will be followed up for prenatal diagnosis results and birth defects. The primary outcome measures are the incidence rates of microdeletion/microduplication, heteroploidy, and LOH. The secondary outcome measures include embryo utilization rate, clinical pregnancy rate, ongoing pregnancy rate, live birth rate, miscarriage rate, concordance rate between prenatal diagnosis results and PGT-A results, and birth defect rate. The maximum follow-up duration will be 1 year after embryo transfer. Clinical and embryology laboratory procedures during the study will not be altered and will be performed in accordance with each center's routine practice.