What is Anencephaly?

Anencephaly is a birth defect that affects the brain and skull development of newborn babies.

It occurs when part of the neural tube fails to close during embryonic development. This results in the absence of the upper portion of the brain and scalp.

This means a newborn cannot develop higher brain functions and is incompatible with life.

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What Causes Anencephaly?

Anencephaly is caused by a neural tube defect when the baby’s skull and brain do not form properly during early pregnancy.

A combination of genetic and environmental factors can cause anencephaly. These factors include insufficient intake of folic acid or other nutrients before and during pregnancy, exposure to some drugs or toxins, and certain infections during pregnancy.

Signs & Symptoms

Common signs and symptoms include:

  • An absence of most or all cranial bones results in a baby with an open, unprotected brain
  • Absence of most or all of the scalp, revealing exposed brain tissue
  • Absence of the cerebrum, which is the largest part of the brain
  • Absence of a functioning brain stem, which controls breathing and heartbeat
  • Abnormal eye development that may include small eyes or no eyes at all
  • Low birth weight
  • Flattened facial features
  • Small head size

Risk Factors

Risk Factors for anencephaly include:

  • Genetics: the risk for anencephaly is higher if there is a family history of neural tube defects or if either parent has a chromosomal abnormality.
  • Using drugs or alcohol during pregnancy can increase the risk for anencephaly.
  • Low folate levels in the mother. Folate, or folic acid, is a vitamin in foods like leafy green vegetables and beans.
  • Certain infections such as toxoplasmosis, rubella, herpes, syphilis, and chickenpox can increase the risk for anencephaly.


Diagnosis is during pregnancy through an ultrasound test.


There is no cure for anencephaly.

CHRISTUS Children's - The Fetal Care Center

When the unexpected fetal anomaly occurs, the Fetal Care Center at CHRISTUS Children's connects pediatric specialists to pregnant women and their families, regardless of where they plan to deliver their baby.

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