- 1 in 50,000 births.
- The cranial cavity is fluid filled and there is no remaining cortex. The falx cerebri and posterior fossa are normal.
- The incidence of chromosomal abnormalities and genetic syndromes is not increased.
- The causes are vascular occlusion in the internal carotid artery, fetal infection or prolonged ventriculomegaly.
- Detailed ultrasound examination including neurosonography.
- TORCH test for fetal infections.
- If pregnancy continues, follow-up should be standard.
- Standard obstetric care and delivery.
- If the head is circumference is >40cm, cephalocentesis may be needed before vaginal delivery.
- Death in early infancy.
- No increased risk of recurrence.