Analysis of chromosomal abnormalities in 325 cases of spontaneous abortion by NGS technique

Objective To detect 325 cases of spontaneous abortion tissues by next generation sequencing (NGS) technology, to investigate the incidence of chromosome number aberration and copy number variation (CNV) in spontaneous abortion. Method A retrospective analysis of the chromosomal abnormalities in chorionic villi collected from 325 patients with spontaneous abortion from November 2014 to November 2017 was performed. Results (1) In 325 cases of abortion tissue, 171 cases of chromosomal abnormalities were detected (171/325, 52.62%). Among 171 cases of chromosomal abnormalities, trisomy was the most common (71.35%). The other chromosomes were detected except for 1, 11, and 19-trisomy, 16-trisomy showed the highest rate (22.22%, 38/171), followed by 22-trisomy (14.04%, 24/171) and 15-trisomy (9.94%, 17/171). 7 cases of double trisomy were detected (4.09%). There were 20 cases (11.70%) of monosomy 45, X, of which 4 cases were combined with trisomy. There were 4 cases (2.34%) of XNN triploid, of which 1 case was combined with trisomy. 3 cases (1.75%) of monosomy Chr21 were detected. 5 cases (2.92%) of chimerism were detected. 10 cases (5.85%) had chromosome duplication or deficiency with CNV≥5 Mb, of which 2 cases were combined with trisomy. (2) The rate of chromosome abnormalities in pregnant women over 35 years old was higher than that in pregnant women 0.05). Conclusion Fetal chromosomal abnormality is the main cause of spontaneous abortion in early pregnancy. The rate of chromosomal abnormalities in older pregnant women is relatively high. The older pregnant women should pay more attention to fetal chromosome examination in early pregnancy. Key words: Next generation sequencing (NGS); Spontaneous abortion; Chromosomal abnormality; Copy number variation