The acardius fetuses or TRAP, consequence of vascular anastomoses in the placenta, may disrupt
organogenesis in the recipient.They are classified as acardius amorphous, acormus, acephalus and anceps.
Diagnosis is now possible during the first trimester by using trasnvaginal 3D Doppler Angiography. Conjoined
twins are variants of monozygotic twins that occur by incomplete dissociation of cells from the internal cellular
mass, especially during the hatching process. Thanatophoric dysplasia is the most common lethal
osteochondrodysplasia. The different skeletal dysplasias, the mentioned, dysostosis, idiopathic osteolisis,
disorders resulting from chromosomal defects and resulting from primary metabolic disorders, are showed by
using their US typical images. Achondroplasias, an autosomal dominant disorder related to a defect in the short
arm of chromosome 4, can be homozygous (lethal) or heterozygous (most live newborn). Osteogenesis
imperfecta includes disorders of the connective tissue and bone fragility, particularly of the skeletal system. Lung
malformations, bronchogenic cyst and cystic adenomatoid malformation have characteristic differential 3D US
images. Cardiac tumors are rear findings and have been identified with fetal echocardiography, improving the
perinatal outcome. Neural tube defects, myelomeningocele and spina bífida, are among the most difficult
malformations to diagnose, requiring considerable experience and the use of 3D. Sacrococcygeal teratomas
represent more than half of all fetal solid tumors. Fetal limb malformations are classified depending on whether
the anomalies are predominantly of bone length or of digital deformities. Congenital multiple arthrogriposis or
joint gryposis describe a syndrome consisting of multiple contractures and joint dislocations of a very poor
perinatal outcome. Gastrointestinal malformations are numerous with different locations and prognosis. We are
showing all of them by using 3D/4D, paying special attention to the most common ones: gastroschisis and
omphalocele. Renal and other urinary tract malformations represent 20% of all congenital anomalies. It is now
possible to detect a wide spectrum using 3D. These may be either isolated or part of polimalformative syndromes.
There are very few reports of intersexes and other Genital malformations. Amniotic band syndrome is
characterized by multiple malformations secondary to amniotic bands that compress fetal parts causing
amputations and other lesions.
