Ultrasound evaluation of fetal chromosome disorders.

Prenatal diagnosis of chromosomal disorders requires an invasive test in women regarded as being at high risk after screening. There is extensive evidence that effective screening for major chromosomal abnormalities can be provided in the first and second trimesters of pregnancy. With the association of some biochemical markers, it is possible to identify about 90% of chromosomal abnormalities. In this article, we aimed to review the important ultrasonographic markers of chromosomal abnormalities, including nuchal translucency, nasal bone, and nuchal skinfold thickness, based on the data available in the literature.