Experience of copy number variation sequencing applied in spontaneous abortion

We evaluated the value of copy number variation sequencing (CNV-seq) and quantitative fluorescence (QF)-PCR for analyzing chromosomal abnormalities (CA) in spontaneous abortion specimens.

A total of 650 products of conception (POCs) were collected from spontaneous abortion between April 2018 and May 2020. CNV-seq and QF-PCR were performed to determine the characteristics and frequencies of copy number variants (CNVs) with clinical significance. The clinical features of the patients were recorded.

Clinically significant chromosomal abnormalities were identified in 355 (54.6%) POCs, of which 217 (33.4%) were autosomal trisomies, 42(6.5%) were chromosomal monosomies and 40 (6.2%) were pathogenic CNVs (pCNVs). Chromosomal trisomy occurs mainly on chromosomes 15, 16, 18, 21and 22. Monosomy X was not associated with the maternal or gestational age. The frequency of chromosomal abnormalities in miscarriages from women with a normal live birth history was 55.3%; it was 54.4% from women without a normal live birth history (P > 0.05). There were no significant differences among women without, with 1, and with ≥ 2 previous miscarriages regarding the rate of chromosomal abnormalities (P > 0.05); CNVs were less frequently detected in women with advanced maternal age than in women aged ≤ 29 and 30-34 years (P < 0.05).

Chromosomal abnormalities are the most common cause of pregnancy loss, and maternal and gestational ages are strongly associated with fetal autosomal trisomy aberrations. Embryo chromosomal examination is recommended regardless of the gestational age, modes of conception or previous abortion status.