In an advanced, high-resolution ultrasound scan which is usually advisable between the 20th and 22nd week of pregnancy, a wide range of fetal developmental anomalies and organ malformation can be diagnosed, some of which are not recognizable in the early stages of pregnancy.
Prenatal diagnosis of congenital anomalies is often very significant for the further course of the pregnancy, birth and the neonatal phase (see below: options, limits and the consequences of prenatal diagnosis). This is particularly true for heart defects (see fetal echocardiography).
In the course of this high-resolution ultrasound scan, the uterus, placenta and amount of amniotic fluid are also assessed. Furthermore, Doppler sonography, fetal echocardiography and – if possible – 3D ultrasound are conducted (as far as the examination conditions permit).