The fetal warfarin syndrome, also known as warfarin embryopathy or di Sala syndrome is caused by fetal exposure to warfarin, an anti-vitamin K anticoagulant used for thromboembolic disorders treatment and prophylaxis, leading to a series of complex malformations, as well as neurological and mental impairment. The disease is more severe if exposure occurs during the first trimester of pregnancy.
The presentation of the fetal warfarin syndrome depends on the quantity of the drug that the mother has ingested, the teratogenicity being dose dependent  and the duration of the fetal exposure to warfarin. The greatest risk is encountered during the sixth and the ninth week of gestation  . The drug has a low molecular weight and crosses the placenta, causing vitamin K deficiency in the embryo or fetus. The mother can present for spontaneous abortion or the pregnancy can be carried to term, but the child may be born dead or die during the neonatal period . When the child survives, he or she has a series of congenital abnormalities  . The facial traits of a fetal warfarin syndrome-affected child include nasal hypoplasia, nose bridge depression, the presence of a groove between the tip of the nose and the alae nasi. Small nostrils resulting from these abnormalities may impair air flow and cause neonatal respiratory distress, that may be severe enough to require intervention. Osseous stippling occurs in the axial skeleton and femurs . It may be accompanied by scoliosis and hypoplasia of the extremities, ranging from rhizomelia to dystrophic nails. Central nervous system and eye malformations occur more frequently when the fetus has been exposed to warfarin during the second and third trimesters of pregnancy. Abnormalities consist of hydrocephalus, microcephaly, corpus callosum agenesis, microphthalmia and optic atrophy. Blindness, deafness, and seizures, as well as severe bleeding at birth, not predictable from the maternal international normalized ratio, may also be seen  . Other teratogenic effects of warfarin include cardiac and laryngeal abnormalities, aortic coarctation, situs inversus totalis, ventral midline dysplasia, bilobed lungs, congenital cataract, short neck, cleft palate and/or lip , mental retardation, feeding difficulties, widely spaced nipples and the Dandy-Walker malformation. Hypotonia or muscular spasticity may be encountered. These children usually fail to thrive.
Fetal warfarin syndrome diagnosis is mostly based on pregnancy history and clinical examination. However, skeleton radiographs can provide additional information, such as the epiphyseal stippling of vertebrae, long bones, and sacrum. These findings are transient and disappear as the child grows older . Scoliosis, as well as short limbs and digits, can also be noticed on radiological films . Epiphyses can be found to be non calcified. These findings are present in 5-12% of infants who were exposed to warfarin between the sixth and the ninth week of gestation.