1Division of Fetal Medicine, Department of Perinatal Medicine and Maternal Care, National Center for Child Health and Development, 2Department of Clinical Laboratory Medicine, National Center for Child Health and Development, 3Department of Perinatal Medicine and Maternal Care, National Center for Child Health and Development, 4National Center for Child Health and Development
Ultrasound screening of the fetus attempts to identify fetal anomalies that will require treatment either before or after birth. The standard ultrasound screening, conducted by a specially trained sonographer or a trained physician, is usually carried out at 20 and 30 weeks gestation. The ultrasound examination consists of an assessment of fetal growth, amniotic fluid, fetal morphology, and placenta and cord; and the fetus is examined at the head, chest (heart and lungs), abdomen (stomach, kidney, and bladder), and spine. Fourteen fetal ultrasound views are acquired in a standard examination. Images showing important fetal anomalies and requiring diagnosis are selected and compared with normal fetal images. Typical abnormalities include hydrocephalus, holoprocencephaly, diaphragmatic hernia, cystic adenomatoid malformation, bronchopulmonary sequestration, hydrothorax, hypoplastic left heart, atrioventricular septal defect, Ebstein anomaly, heterotaxy syndrome, gastroschisis, omphalocele, esophageal atresia, duodenal atresia, jejunal atresia, hydronephrosis, multicystic dysplastic kidney, polycystic kidney, myelomeningocele, and sacrococcygeal teratoma.