Fetal Anomalies

Screening ultrasound examination may be carried out as early as the first trimester via both transabdominal and transvaginal modalities in combination with technologies such as three-dimensional and four-dimensional ultrasound. By 12 weeks, approximately 40–50 % of common ultrasound discernable anomalies are already present. Ultrasound in the first trimester allows identification of up to 80 % of lethal and major fetal anomalies. The fetus and non-fetal obstetric structures may be examined in detail. Distinctive features of anomalies of the fetal head, neck, face, trunk, abdomen, extremities, and umbilical cord are discussed. It is clinically relevant to identify anomalies as early as possible to enable proper counseling and maternal fetal care.