anencephaly is a serious birth defect in which a baby is born without parts of the brain and skull. It is a type of neural tube defect (NTD). As the neural tube forms and closes, it helps form the baby’s brain and skull (upper part of the neural tube), spinal cord, and back bones (lower part of the neural tube).
Anencephaly happens if the upper part of the neural tube does not close all the way. This often results in a baby being born without the front part of the brain (forebrain) and the thinking and coordinating part of the brain (cerebrum). The remaining parts of the brain are often not covered by bone or skin.
How Many Babies are Born with Anencephaly?
Researchers estimate that about 1 in every 4,600 babies is born with anencephaly in the United States.1
Causes and Prevention
The causes of anencephaly among most infants are unknown. Some babies have anencephaly because of a change in their genes or chromosomes. Anencephaly might also be caused by a combination of genes and other factors, such as the things the mother comes in contact with in the environment or what the mother eats or drinks, or certain medicines she uses during pregnancy.
Getting enough folic acid before and during early pregnancy can help prevent neural tube defects, such as anencephaly.