Clinical Transfer Outcomes of Embryos With Non-Mosaic Segmental Aneuploid Results on the Pgtseq-a Assay: A Retrospective Chart Review.

Objective: To describe clinical transfer outcomes of embryos with non-mosaic segmental aneuploid (NMSA) results on preimplantation genetic testing for aneuploidy (PGT-A) using the PGTSeq-A assay. Design: Retrospective chart review. Materials and Methods: A retrospective chart review was conducted of all patients who pursued transfer of an embryo with NMSA results tested on the PGTSeq-A platform between May 2022 and September 2024. All patients had genetic counseling prior to the start of their cycle and all transfers were single-embryo transfers (SETs). Patient age, number of IVF cycles completed, PGT-A results and frozen embryo transfer (FET) outcomes were collected. Where available, results of products of conception (POC) or prenatal testing were reviewed. Descriptive analyses were performed to examine patient outcomes, which are reported as median, proportions, and number of cases. Results: A total of 39 patients met inclusion criteria for further analysis. The group had a median age of 38 (interquartile range 33-42). Most patients (25/39) were nulliparous and had completed a median number of 2 IVF cycles. 38 embryos were transferred through SET; one did not survive thaw. 10 FETs resulted in a positive bHCG (26% - 10/38). The implantation rate was 16% (6/38) and the clinical miscarriage rate was 33% (2/6). Two patients have ongoing pregnancies and two delivered term infants who are reportedly healthy. POC testing for one loss showed an isodicentric structural alteration affecting the same chromosome as the NMSA. Amniocentesis results received for one ongoing pregnancy were negative for abnormalities. Conclusions: Embryos with non-mosaic segmental aneuploid results on the PGTSeqA assay can result in livebirth, albeit at a low rate. While embryos with NMSA results have traditionally been excluded for transfer or discarded, our data suggest this practice should be re-examined.