Cytogenetic analysis of 2959 couples with spontaneous abortion and detailed analysis of rare karyotypes.

Chromosome abnormality is one of the important causes of spontaneous abortion. However, due to regional and ethnic differences, the reported rates of chromosomal abnormalities in patients with spontaneous abortion vary greatly. At present, there is no large sample statistics of chromosome abnormality in patients with spontaneous abortion in Yantai, Shandong province, China and hence 2959 couples (5918 individuals) with spontaneous abortion were recruited for this study. G banding was used to examine the karyotype of patients. The results showed that chromosomal abnormalities were present in 173 of 2959 couples with the rate of 5.85%. Female carriers were significantly higher than male. Chromosomal abnormality rate was positively correlated with the number of spontaneous abortions. Structural aberrations were significantly greater than numerical aberrations, with a prevalence of 92.49% and 7.51%, respectively. Balanced translocation, Robertson translocation and inversion were the most common types of chromosomal structural abnormalities. Among them, the proportion of balanced translocation was the highest (63.13%, 101/160). In addition, three cases of rare complex abnormal karyotype were detected. In summary, chromosome abnormality could be one of the important causes of spontaneous abortion in Yantai, Shandong province, China. The sex of patients with chromosomal abnormalities and the number of spontaneous abortions should be considered in genetic counselling. When one of the partners have chromosome abnormality, preimplantation genetic diagnosis and prenatal diagnosis could play a great significance for preventing the birth of children with chromosomal diseases and reducing birth defects.