When the closure defect occurs lower down, it gives rise to a condition commonly referred to as spina bifida. It is of different types and the severity of the condition depends on the extent of the defect. Some patients with less severe types of spina bifida may live for many years with mild disabilities. In it’s most severe form, it is characterized by paralysis or weakness below the level of the defect. In case of Hydrocephalus, there is an abnormal accumulation of the cerebrospinal fluid in the brain, leading to head enlargement in the fetus. Patients with such defects often have very poor control in terms of the bowel and bladder habits (Incontinence- inability to control urination or passage of stools). 

Detection of Neural Tube Defects

Prenatal diagnosis:

Prenatal diagnosis refers to diagnosis of certain birth defects by conducting tests before the child is born.

If there is positive history of a previous child with a neural tube defect, there is a greater possibility of the disorder occurring in subsequent child. In fact, in most of the cases, it is usually the birth of a first child with NTD that indicates prenatal diagnosis to prevent the second one in the family.

General prenatal screening for neural tube defects can be done by testing the blood of the pregnant woman for a- fetoprotein. The chemical a- fetoprotein is made in the fetal liver but its function is unknown. Small amounts of the substance are present in the amniotic fluid in normal fetuses. Higher than the normal levels of the chemical in the amniotic fluid of fetuses indicate Spina bifida and anencephaly. The testing is usually done between the sixteenth to eighteenth week of pregnancy. However, A high level of a- fetoprotein does not always mean that the fetus is defective, because other reasons could be responsible for the same. Ultrasonography and amniocentesis are indicated in the group of pregnant women with elevated levels of a- fetoprotein to confirm the diagnosis.