[Ultrasound indications of fetal chromosome abnormalities in the 2nd trimester]

The most common fetal chromosomal disorders have structural abnormalities, which can be detected during second trimester ultrasound examination. Major malformations, also known as hardmarkers, when single or in combination, should raise the suspicion for a specific syndrome. But it is known, that even more subtile findings can increase the background risk based on the maternal age, especially for Down syndrome. A combination of these so called "soft-markers" can be used for second trimester screening in a high and low risk population. Here were report on the sonographic features of the common chromosomal anomalies and their significance in prenatal diagnosis.