Anencephaly is a fatal birth defect that occurs when the infant's brain and skull do not fully form during pregnancy. Statistically speaking it is fairly common, occurring in one out of approximately every one thousand births. For reasons unknown, Hispanics have a higher incidence of anencephaly than other ethnic groups.
During the first month of pregnancy the neural tube forms the baby's brain and skull from the upper section and the baby's spinal cord and vertebrae from the lower section. If the upper section of the neural tube fails to close the brain forms without the forebrain and the cerebrum. The forebrain controls voluntary movements and the cerebrum controls thinking and coordination. The brain matter that does grow may not be covered with skin or bone. Some babies born with anencephaly also have facial deformities and heart defects. Most die within hours after birth; some may survive a few days but the birth defect is 100% fatal.
The reason anencephaly occurs is unknown but in recent decades a strong connection has been made between folic acid intake and neural tube birth defects. The demand for folic acid in the developing child is highest in the first month during which time the brain and spine form and the neural tube closes. Women who do not know they are pregnant are not aware of the consequences of inadequate folic acid in their bodies. Women who are planning a pregnancy should begin taking folic acid supplements at least one month prior to conception. Since many pregnancies are unplanned, women of childbearing age should take folic acid supplements as a precautionary measure. Folic acid must be taken in supplement form; even the healthiest of diets does not provide adequate amounts to prevent neural tube defects. Anencephaly is usually detected during prenatal ultrasounds so most parents are aware that their child will be born with the condition if they choose to carry the child to term.