Anencephalus (also called Anencephaly)


Condition Description

Anencephalus (AN–en–SEF–ah–lus) is a severe neural tube birth defect that is almost always incompatible with an infant’s survival. In the third and fourth week of fetal life the embryo’s cells fail to fold over and close to form a channel that becomes the brain. This results in an absence of a major portion of the brain, skull and scalp. The babies with anencephalus do not have a forebrain or cerebrum (the major ”thinking“ structure of the brain), and the remaining brain tissue is often not covered by bone or skin. The baby will be blind, deaf, unconscious and unable to feel pain. Reflex actions such as breathing and responses to sound or touch may be present in some babies. The cause is unknown but is probably an interaction of genetic factors with environmental risk factors (nutritional deficits, environmental toxins). Increasing the folic acid consumption of women of child-bearing age is expected to significantly reduce the incidence of neural tube defects, including anencephalus.


About 1,000–2,000 babies with anencephaly are born in the US each year. Mothers who have had one child with anencephaly have about a 3% chance of having another with the condition.

Common Associated Conditions

Babies with anencephalus are often stillborn. They may have other defects, typically of midline areas of the body, such as cleft palate, and 10-20% of affected infants have congenital heart defects. They may also have ear malformations since the ears develop at a similar time of fetal life as the midline brain structures.

Short-Term Treatment and Outcomes

Because of the absence of brain tissue, parents will be informed about the baby's grave condition, and comfort care will be given to the baby and family.

Long-Term Treatment and Outcomes

Babies usually live just a few hours or days. Families are supported to spend as much time as they wish with the baby who is kept comfortable and free of discomfort. Families will be offered genetic counseling and grief counseling.

This condition is incompatible with a life span of more than a few hours or days. The birth of a severely affected child is very difficult and families will find support from other families who have experienced similar circumstances. Support groups can be found on the internet as well as in many communities.

Parental education and support are essential, and local, regional and national organizations may be very helpful.