Presentation
Patient came for her second-trimester scan (16 weeks gestation).
Patient Data
On ultrasound examination of the fetus, the calvaria and brain parenchyma were not visualized. Biparietal diameter and head circumference could not be measured.
A "coronal" section through the fetal face shows frog-like bulging of eyes and absent frontal bones.
The transvaginal scan (TVS) demonstrates the fetus in sagittal view.
Case Discussion
Anencephaly is a lethal congenital anomaly which can be detected on ultrasound as early as 11 weeks of gestation.
If some amount of neural tissue is present, the condition is termed exencephaly.
Polyhydramnios is usually associated with neural tube defects. Associated anomalies should be sought, including spinal dysraphism, diaphragmatic hernia and amniotic band syndrome.
Maternal serum alpha-fetoprotein levels are raised in all types of neural tube defects.
Folic acid supplements for women of reproductive age are helpful for the prevention of neural tube defects. No treatment option is available for anencephaly.