ABSTRACT
The value of ultrasonic markers in the detection of chromosomopathies is now very well established. Various sonographic markers have been proposed for detecting fetuses with aneuploidy, including a thickened nuchal fold, shortened long-bone measurements, and the ratio of biparietal diameter (BPD) to femur length. 1 , 2 A combination of sonographic aneuploidy markers has been shown to increase sensitivity and to decrease the number of unnecessary invasive diagnostic procedures. 3 , 4 Therefore, it is reasonable to continue searching for further sonographic markers in an attempt to further increase the prenatal detection rate of chromosomal abnormalities. In this way, in a population of high-risk women, when one or more of these markers are visualized by sonography, the sensitivity for the detection of aneuploidy may be increased. Conversely, in high-risk women who want this information, the absence of such markers can decrease the a priori risk of aneuploidy to levels low enough to avoid amniocentesis and its possible complications. In this chapter, we will review the use of three-dimensional (3D) sonography in this important field.
