Abstract: The chromosomal abnormalities are usually 21, 13, 18 chromosomes and the sex chromosome aneuploids. The results of serum screening is that the high-risk and the age over 35 pregnant women are required for prenatal diagnosis. Traditional karyotyping is considered the gold standard for invasive prenatal diagnosis, but the results take 2-3 weeks. With the rapid development of molecular biology, polymerase chain reaction used in aneuploidy of prenatal diagnosis. Polymerase chain reaction is high sensitivity and specificity, simple operation, short cycle test, is suitable for the detection of fetal aneuploidy.

Key words: Polymerase chain reaction, Aneuploidy, Prenatal diagnosis, Application