A lethal fetal anomaly
Severe open neural tube defect of the calvaria and skin leading to complete obliteration of the fetal cerebrum.
Anencephaly is a severe congenital defect in which the rostral neuropore fails to close during the first month of gestation, resulting in failure of the development of the forebrain. Anencephaly is often accompanied by a variety of other malformations, including defects of the skull, facial abnormalities, and ocular abnormalities. Anencephaly is not compatible with life and the treatment of neonates who survive birth is palliative, since the majority of neonates expire within days or weeks. Folate deficiency is the most common and important risk factor for anencephaly, as well as caudal neural tube defects (eg, spina bifida). The use of medications such as trimethoprim and antiepileptics also increases the risk for anencephaly. Daily supplementation of folate is recommended for all pregnant women and for those who are considering pregnancy
Anencephaly is diagnosed by fetal ultrasound, which typically reveals an absent cerebrum, a calvarial defect, an abnormal cerebellum or brainstem, and elevated amniotic fluid volume (ie, polyhydramnios due to impaired fetal swallowing).
