Abstract: OBJECTIVE： To determine chromosomal aneuploidy and related factors in first-trimester spontaneous aborted tissues. METHODS： Conducted detection of aneuploid chromosomes and microduplication or micro-deletion of gene fragments which are larger than 100 kb， and retrospective analysis to find the incidence of chromosomal abnormalities in products of conceptions (POC). Compared with existing literature to identify related factors. RESULTS： Among the 56 cases with abnormal karyotypes，46 cases had abnormal number of chromosomes. The number of cases with abnormal chromosomes was higher than that with normal chromosomes. Frequencies of micro-duplicates or micro-deletions of gene fragments were associated with ages of pregnant women (P=0.004). The abnormal rate of these micro-duplicates or micro-deletions increased with maternal age and gravidity (P<0.05). CONCLUSION： Presence of chromosomal abnormalities in early spontaneously aborted tissues indicate that these abnormalities were the main cause of miscarriage in the first trimester. For couples with early spontaneous abortion，cytogenetic examination should be performed on all of POC.

Key words: spontaneous abortion, chromosome aberrations, copy number variants, gravidity