Anencephaly
is a birth defect that affects the closing of the neural tube during
pregnancy. The neural tube is a narrow channel that folds and closes
during the third and fourth weeks of pregnancy to form the brain and
spinal cord. Anencephaly occurs when the portion of the neural tube
that forms the brain does not close. This results in the baby
lacking parts of the brain, skull, and scalp. Babies with this
condition often 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; that is, it is
not covered by bone or skin.
To learn more about anencephaly click on one of the following links
or scroll down the page.
What We Know About Anencephaly
- How often does anencephaly occur?
- What problems do children with anencephaly have?
What We Still Do Not Know About
Anencephaly
- What causes anencephaly?
- Can anencephaly be prevented?
Resources for Families and Individuals
Affected by Anencephaly
| What
We Know About Anencephaly |
How often does anencephaly occur?
CDC estimates that each year about 1,000 babies in the United States
will be born with anencephaly (1). In other words, about 1 in every
4,000 babies born in the United States will have anencephaly.
What problems do children with anencephaly have?
Unfortunately, almost all babies born with anencephaly will die.
Babies born with anencephaly are usually blind, deaf, unconscious,
and unable to feel pain. Various studies have shown the survival of
infants with anencephaly to be almost impossible. A 2001 study found
that, among a group of infants in Texas, all of those with
anencephaly died before 1 year of age (2).
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| What
We Still Do Not Know About Anencephaly |
What causes anencephaly?
The cause of anencephaly is unknown. Scientists believe that many
factors are involved.
We at CDC work with many researchers to study risk factors that can
increase the chance of having a baby with anencephaly. Following are
examples of what our research has found:
- Hispanic babies are at an increased risk for anencephaly
(3).
- We have found a 21% decline in the birth rate of babies born
with anencephaly since the United States began fortifying grains
with folic acid (4).
Can anencephaly be prevented?
Currently, there is no known way to prevent anencephaly, although
steps can be taken to lower the risk. Recent studies have shown that
the addition of a B vitamin called folic acid to the diet of women
who might become pregnant can greatly reduce the number of babies
born with neural tube defects. CDC recommends that all women of
childbearing age consume 400 micrograms of folic acid daily. A
single serving size of most multivitamins and fortified cereals
contains 400 micrograms of folic acid.
In addition, women can take steps before and during pregnancy to be
healthy, including not smoking and not drinking alcohol during
pregnancy.
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|
Resources for Families and Individuals Affected by
Anencephaly |
National Institute of Neurological Disorders and Stroke
National Organization for Rare Disorders
References
- Canfield MA, Honein MA, Yuskiv N, Xing J, Mai CT, Collins
JS, et al. National estimates and race/ethnic-specific variation
of selected birth defects in the United States, 1999-2001. Birth
Defects Res Part A Clin Mol Teratol. 2006;76(11):747–56.
- Nembhard WN, Waller DK, Sever LE, Canfield MA. Patterns of
first-year survival among infants with selected congenital
anomalies in Texas, 1995-1997. Teratology. 2001;64:267–75.
- Williams LJ, Rasmussen SA, Flores A, Kirby RS, Edmonds LD.
Decline in the prevalence of spina bifida and anencephaly by
race/ethnicity: 1995-2002. Pediatrics. 2005;116(3):580–6.
- Centers for Disease Control and Prevention. Spina bifida and
anencephaly prevalence--United States, 1991-2001. MMWR Morb
Mortal Wkly Rep. 2002;51:9–11.
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Date:
March 11, 2009
Content source: National Center on Birth Defects and Developmental
Disabilities
