Neural Tube Defects

Neural tube defects (NTDs) are among the most common anomalies diagnosed prenatally and occur as a failure of the neural tube to close during the embryonic period. The resulting defect may involve the vertebrae, spinal cord, cranium, and/or brain. NTDs are classified as open or closed depending on the absence or presence of the fetal skin above the defect. Open NTDs are defects commonly covered only by a membrane. The most common NTDs include myelomeningocele (open spina bifida) and anencephaly. Prenatal diagnosis by ultrasound is the mainstay for the detection of these anomalies before birth with reported high diagnostic performance for these anomalies, except that for closed spinal defect. The aim of the present chapter is to provide an up to date on the pathophysiology, prenatal diagnosis, and prognosis of fetuses with NTDs.