Anencephaly is a cephalic disorder that results from a neural tube defect that occurs when the cephalic (head) end of the neural tube fails to close, usually between the 23rd and 26th day of pregnancy citation needed, resulting in the absence of a major portion of the brain, skull, and scalp. Children with this disorder are born without a forebrain, the largest part of the brain consisting mainly of the cerebral hemispheres (which include the is cortex, which is responsible for higher level cognition, i.e., thinking). The remaining brain tissue is often exposed - not covered by bone or skin.

Anencephaly occurs when the "cephalic" or head end of the neural tube fails to close, resulting in the absence of a major portion of the brain, skull, and scalp. Infants with this disorder are born without a forebrain (the front part of the brain) and a cerebrum (the thinking and coordinating part of the brain). The remaining brain tissue is often exposed--not covered by bone or skin. A baby born with anencephaly is usually blind, deaf, unconscious, and unable to feel pain. Although some individuals with anencephaly may be born with a rudimentary brain stem, the lack of a functioning cerebrum permanently rules out the possibility of ever gaining consciousness. Reflex actions such as breathing and responses to sound or touch may occur.

Anencephaly may be associated with the unbalanced form of a structural chromosome abnormality in some families. In these cases, other malformations and birth defects that are not usually found in isolated cases of anencephaly may be present. Amniotic band disruption sequence is a condition resulting from rupture of the amniotic membranes. This can cause disruption of normally formed tissues during development, including the structures of the head and brain. Anencephaly caused by amniotic band disruption sequence is frequently distinguishable by the presence of remnants of the amniotic membrane. Recurrence risk for anencephaly caused by this mechanism is lower and the risk is not modified by the use of folic acid.

Anencephaly is a congenital birth defect that occurs in approximately one in one thousand pregnancies. It is a neural tube defect, just as is spina bifida. Life expectancy for a baby with anencephaly after birth is just a few hours, sometimes a few days at most.
As the malformation is usually detected during a pre-natal scan, parents are confronted with a choice between life and death. A choice often made with very little information of what is in store for them. It is with this in mind that we have made the choice to share the stories of the brief, but wonderful lives of babies with anencephaly. We hope that it will be of help to you and impart courage.

Some of the environmental factors include uncontrolled diabetes in the mother, and certain medications that are available by prescription only. According to the Centers for Disease Control and Prevention (CDC), the occurrence rate of ONTDs can vary from state to state and from country to country. The rate of ONTD occurrence in Arkansas is 7.8 out of 10,000 births and 30 out of 10,000 births in Washington. The country with the highest number of documented cases is Ireland, where spina bifida occurs in approximately 4.2 out of 1,000 live births. The environmental factors causing these differences are not well understood.