While several fetal anomalies can be diagnosed early in the pregnancy, second-trimester ultrasound can identify or exclude even more conditions. The second slideshow of our ultrasounds collection includes the second-trimester anomalies of the body and limbs that shouldn't be missed.For more information on first-trimester anomalies and second-trimester anomalies discussed anomalies of the head and brain, check out Part 1 of the series.More information on ultrasound diagnoses can be found in, 'Using ultrasound to recognize fetal anomalies.'
Diaphragmatic hernia should be suspected if abdominal contents are visible in the chest in the presence of a mediastinal shift. (Left-sided diaphragmatic hernia).
Second trimester right sided diaphragmatic hernia
A 4-chamber view can identify defects of the ventricular spectrum and abnormalities of chamber size such as hypoplastic right or left ventricles.
Major conditions such as Tetralogy of Fallot will have a normal 4-chamber view of the heart in most cases, but will usually be apparent if the outflow tracts are included.
Second trimester transposition of the great vessels
Omphalocele should not be missed in the first semester and definitely should not be missed in the second trimester.
Second trimester gastroschisis
Unilateral renal agenesis or ectopic kidney may be missed, as the adrenal gland or adjacent bowl can be mistaken for a kidney in the renal fossa.
Second trimester unilateral multicystic dysplastic kidney
Disorders affecting both kidneys are associated with oligohydramnios and are seldom missed.
Spina bifida can be suspected based on sagittal imaging.
Smaller lesions associated with spina bifida may only be visible with transverse imaging.
Sagittal imaging can identify hemivertebra.
Quantitative abnormalities involve abnormal growth of the long bones of the arms and legs, such as limb reduction defects.
Qualitative abnormalities of bones include conditions leading to abnormal appearances, such as bowing, fractures, or hypomineralization.
Assessment of hands should include attempts to rule out polydactyly and syndactyly.
Assessment of the feet should include their position relative to the tibia and fibula to rule out signs of clubfoot deformity.
Abnormal tone, such as fixed extension of the legs or clenching of the fingers can indicate a neurologic, neuromuscular, or musculoskeletal abnormality.
Skeletal dysplasias can involve abnormalities of structures other than the arms and legs, including a bell shaped chest.
