Anencephaly at 12+1 weeks of gestation

(A) Sagittal view of the fetus. Note the unusual shape of the fetal head and the lack of surrounding cranium.
(B) Transverse section showing the abnormal shape of the head, with some dysmorphic brain tissue "hanging" from the side of the head. The orbits are prominent. The amniotic fluid is echogenic as compared with the surrounding extraembryonic space; this is due to tissue debris from the disintegrating brain.
(C) Three-dimensional ultrasound reconstruction of the fetus demonstrating the abnormal head shape. Arrows in each image point to the fetal head.