[Chromosome abnormality rate and related factors of spontaneous abortion in early pregnancy]

Objective: To investigate chromosome abnormality rate and related factors of spontaneous abortion in early pregnancy. Methods: A total of 831 tissue samples of spontaneous abortion in early pregnancy were collected from June 2015 to August 2018 in the First Affiliated Hospital of Nanjing Medical University. Chromosomal copy number was analyzed by next generation sequencing (NGS). The relationships between chromosome abnormality and maternal age, in vitro fertilization-embryo transfer (IVF-ET) pregnancy, number of previous spontaneous abortions, history of live birth were analyzed by statistical methods. Results: Among 831 tissue samples of spontaneous abortion in early pregnancy, 461 (55.5%, 461/831) were found to have chromosome abnormalities. Maternal age (OR=1.107, 95%CI: 1.070- 1.145) and history of live birth (OR=1.909, 95%CI: 1.182-3.083) were the positive correlative factors of chromosome abnormality. Times of previous spontaneous abortion (OR=0.807, 95%CI: 0.702-0.928) and IVF-ET pregnancy (OR=0.554, 95%CI: 0.404-0.760) were the negative correlative factors of chromosome abnormality. Conclusions: Chromosome abnormality is an important cause of spontaneous abortion in early pregnancy. The rate of chromosome abnormality increases with the increase of maternal age and the history of live birth, and decreases with the increase of number of previous spontaneous abortion and IVF-ET pregnancy.