Chromosomal analysis of 262 miscarried conceptuses: a retrospective study

Embryonic chromosomal abnormality is one of the significant causative factors of pregnancy loss. Our goal was to investigate the differences of chromosomal abnormality between different conception modes in miscarried products of conception (POCs).

A retrospective study included 262 miscarried POCs from 167 women undergoing assisted reproductive treatment (ART) and 95 spontaneous pregnant (SP) women during March 2019 to March 2022 in Renmin Hospital of Wuhan University. Subgroups were divided according to age, fertilization method, types and stages of embryo transfer. The profiles of cytogenetic abnormalities in the miscarried POCs were measured via next-generation sequencing.

The rate of chromosomal abnormality in the fresh embryo transfer group and the cleavage embryo transfer group was significantly higher than that in the frozen embryo transfer group (79.2% vs. 36%, P = 0.0001) and the blastocyst transfer group (66.7% vs. 32.1%, P = 0.0001) respectively. There was no significant difference in the rate of chromosomal abnormalities when compared by maternal age (49.2% vs. 62%, P = 0.066), types of conception (49.7% vs. 57.9%, P = 0.202), fertilization method (49.6% vs. 48.7%, P = 0.927) and frequency of abortion (56% vs. 47.6%, P = 0.183). However, the women aged ≥ 35 years had more frequent numerical abnormality (P = 0.002); patients using assisted reproductive technology had more rate of chromosomal structural abnormalities (26.5% vs. 7.3%, P = 0.005); the ICSI fertilization group has more frequency of deletion/microdeletion than the IVF fertilization group (80% vs. 31.3%, P = 0.019).

Blastocyst transfer might help to reduce the incidence of miscarriage. In addition, "freezing all" should be considered if encountered hyper ovarian stimulation, to avoid the negative effect of high estrogen environment on embryo development. The higher incidence of structural abnormalities in miscarried POCs from assisted reproductive patients reminds us to pay attention to the safety of the technology for offspring.