Information About the Disorder
If you or a loved one has an unborn child with a diagnosis of anencephaly, the news can be devastating. While no amount of information can truly mitigate the sense of loss that accompanies this diagnosis, learning about the disorder is necessary for understanding the situation and beginning to work through it.
What is Anencephaly?
Anencephaly is a neural tube birth defect that occurs when the neural tube of a fetus fails to close. This defect happens early on in a pregnancy -- between the third and fourth weeks -- and severely affects the development of the brain. This defect keeps the forebrain and cerebrum from developing; these are the parts of the brain that are responsible for conscious thought, coordination, and all voluntary actions of the body. The remaining part of the brain is usually exposed, without tissue or an enclosing skull.
What is the Prognosis for a Child With Anencephaly?
The prognosis for a child with anencephaly is extremely poor. Because the child lacks much of their brain, they will not be able to think, feel, or experience consciousness. Newborn anencephalic children are usually deaf and blind, and they cannot feel pain. While anencephalic newborn infants may be able to breathe or respond to touch or sound, they are not actually consciously reacting to these stimuli; the reaction is involuntary and comes from the brain stem, the oldest part of the brain at the base of the neck.
Children born with anencephaly are only expected to live a few hours, days, or weeks. Seventy-five percent of anencephalic births are still births, while the remaining 25 percent of infants die shortly thereafter.
What Causes Anencephaly?
The cause of anencephaly is not known, though it is believed to be a mixture of environmental and genetic factors. It is one of the most common neural birth defects and occurs in one to two babies in every 1,000 live births. It is related to spina bifida, a neural birth defect that causes children to be born with an exposed spine.
One environmental cause of anencephaly may be a lack of adequate folic acid in the mother during the pregnancy; getting the recommended dosage of folic acid may reduce neural birth defects by 50 percent. Other environmental factors include taking certain prescription medications while pregnant, and diabetes in the mother. Ninety percent of couples who have a child with anencephaly do not have a family history of the disorder; the genetic basis of anencephaly comes from a combination of both partners’ genes.
The rates of open neural tube defects vary by state; Washington experiences high rates, with 30 out of 10,000 babies being born with some neural defect, while the rate is only 7.8 per 10,000 births in Arkansas. The environmental circumstances that cause such a difference between regions is not understood.
Sources:
Anencephaly. (2011) Children’s Hospital Boston.
NINDS Anencephaly Information Page. (2010) National Institute of Neurological Disorders and Stroke.