Abstract: Objective: To evaluate the risk of abnomal fetus through analysis on karyotypes of advanced maternal age. Methods: Villus chromosome karyotype analysis was performed for 897 pregnant women. Results: 64 abnormal chromosomal karyotypes and 54 de novo abnormal chromosomal karyotypes were detected by prenatal diagnosis, including 14 sex chromosome abnormalities, 27 autosome chromosome number abnormalities, and 13 autosome chromosome structural abnomalities, 10 polyploidy. Conclusion: The risk of the fetus with chromosome abnormalities in the pregnant women aged over 35 years was high and chromosome karyotype analysis was necessary and effective in prenatal diagnosis.

Key words: advanced maternal age, the first trimester of gestation, villus, chromosome abnormalities, chromosomekaryotypeanalysis