Variations in chromosomal aneuploidy rates in IVF blastocysts and early spontaneous abortion chorionic villi.

Purpose: To compare chromosomal aberrations and aneuploidy features in (i) blastocysts following intracytoplasmic sperm injection (ICSI) and trophectoderm (TE) biopsy using preimplantation genetic screening (PGS) and (ii) early spontaneous abortion chorionic villus biopsies (SA-CVB) using single-nucleotide polymorphism (SNP) array detection.

Methods: We retrospectively reviewed the data for 1014 TEs from 220 PGS cycles and 1724 SA-CVBs originating from naturally pregnant couples and patients undergoing assisted reproductive technology (ART) during 2017 to 2018. SNP array was applied in both PGS and SA-CVBs detection. Aberrations were defined, and the frequency and ratio of each chromosome aberration were compared between the two groups.

Results: There were more abnormalities in TEs in the form of complex chromosome aneuploidies and monosomies, while SA-CVBs had more trisomies, sex chromosome abnormalities, and polyploidies. In both groups, chromosomal aneuploidies (including monosomies and trisomies) were confined to chromosomes 14, 15, 16, 18, 21, and 22, but showed varying distributions across the groups. Aneuploidy of chromosome 22 was most frequent in TEs, whereas that of chromosome 16 predominated in SA-CVBs. Among the sex chromosome abnormalities, X monosomies were significantly more prevalent in SA-CVBs.

Conclusions: Chromosomal aberrations and aneuploidy manifested specific characteristics that differed between TEs and SA-CVBs, which indicates that distinct chromosomal abnormalities can affect certain developmental stages of embryos. Further analysis is needed to explore the chromosomal mechanisms affecting embryo development and implantation. Such information will help clinical assessments in prenatal diagnosis and reduce the incidence of genetically abnormal fetuses.