Neural tube defects

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Normally, in human embryos, the closure of the neural tube occurs around the 30th day after fertilization. However, if something interferes and the tube fails to close properly, a neural tube defect will occur.

The incidence of neural tube defects is 2.6 in 1,000 worldwide.

Causes

Pregnant women taking medication for epilepsy have a higher chance of having a child with a neural tube defect. Research has shown that women with folic acid deficiencies also have a higher chance of having a child with a neural tube defect, but this is only one factor. Taking folic acid does not completely negate the risk of neural tube problems, but it does significantly reduce the risk.

Prevention

In Canada, mandatory fortification of selected foods with folic acid has been shown to reduce the incidence of neural tube defects by 46%^[1].

Women who are or could become pregnant are advised to take daily supplements of folic acid, unless their dietary intake of this nutrient is normally high.

Detection

Neural tube defects may be detected by a variety of methods, including some prenatal screening tests and medical imaging. Often, these defects are apparent at birth, but occult defects may be not diagnosed until much later in life.

Types of neural tube defects

Anencephaly
Encephalocele
Spina bifida including myelomeningocele and others

References

↑ De Wals P, Tairou F, Van Allen MI; et al. (2007). “Reduction in neural-tube defects after folic acid fortification in Canada”. N Engl J Med. 357 (2): 135&ndash, 142.