Ultrasound prenatal diagnosis of structural abnormalities

One of the major roles of ultrasound in pregnancy is the detection of structural abnormalities. Ultrasound screening has become an accepted part of antenatal practice. However there is a wide variety in the practice between different centers. The majority of fetal anomalies are diagnosed by ultrasound in the second trimester. However, a number of abnormalities are amenable to diagnosis as early as 11–14 weeks gestation. National guidelines have been adopted in an attempt to standardize the practice in the UK. Prenatal detection rate is higher in countries with a national screening program. Prenatal ultrasound is a screening test and will have false negatives and positives.

Structural abnormalities can occur as isolated events, as part of a genetic syndrome or as a result of a chromosomal abnormality. When an abnormality is detected prenatally, a multidisciplinary approach is necessary to optimize the outcome. It is important to provide appropriate information to the prospective parents but remain non-judgmental with their decision.