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Anencephaly vs. Microcephaly: What's the Difference?

Edited by Janet White || By Harlon Moss || Published on January 5, 2024
Anencephaly is a congenital condition where a major portion of the brain, skull, and scalp is absent, while microcephaly is characterized by a significantly smaller than normal head size due to abnormal brain development.

Key Differences

Anencephaly occurs when the upper part of the neural tube fails to close during embryonic development, leading to the absence of major parts of the brain and skull. Microcephaly is a result of the brain not developing properly during pregnancy or ceasing to grow after birth.
In anencephaly, most of the brain and skull do not develop, often resulting in stillbirth or survival for only a few hours to days after birth. Microcephaly presents as a significantly smaller head circumference compared to babies of the same sex and age.
Anencephaly can be caused by a combination of genetic and environmental factors, including folic acid deficiency. Microcephaly can be caused by genetic abnormalities, exposure to toxins, or infections during pregnancy.
Anencephaly is usually detected by ultrasound during pregnancy, often leading to a decision on pregnancy management. Microcephaly can be diagnosed at birth or later as the child grows and develops.
There is no cure for anencephaly, and the focus is on comfort care. Microcephaly’s management depends on its severity; mild cases may require minimal treatment, while severe cases may need lifelong care.

Comparison Chart


Absence of major brain and skull parts
Significantly smaller head and brain size


Neural tube defect, genetic/environmental
Genetic, environmental, infections

Physical Appearance

Missing skull and brain sections
Smaller head circumference


Prenatal ultrasound
Birth or postnatal development


Generally fatal shortly after birth
Varies, can range from mild to severe

Anencephaly and Microcephaly Definitions


A neural tube defect resulting in missing parts of the brain and skull.
Cases of anencephaly have led to increased focus on folic acid intake during pregnancy.


An abnormality in which brain growth is impaired, leading to a smaller head.
Research into microcephaly focuses on genetic and environmental factors.


A birth defect characterized by incomplete development of the brain and skull.
Medical studies aim to understand the causes of anencephaly better.


A medical condition where a baby's head is much smaller than expected.
Microcephaly was diagnosed in the baby shortly after birth.


A fatal congenital anomaly with a significant absence of brain and cranial structures.
Anencephaly, although rare, is a devastating diagnosis for expecting parents.


A developmental disorder causing smaller than normal brain and head size.
Microcephaly can vary in severity, impacting cognitive development.


A severe congenital condition lacking a major portion of the brain, skull, and scalp.
Anencephaly is a tragic condition often detected during prenatal screenings.


A congenital condition resulting in a significantly reduced head circumference.
Children with microcephaly often require specialized care and treatment.


A condition where the upper part of the neural tube fails to close properly.
Preventive measures for anencephaly include adequate prenatal nutrition.


A condition where the brain does not develop properly, affecting head size.
Early intervention can help manage some of the challenges of microcephaly.


Congenital absence of most of the brain and spinal cord.


Abnormal smallness of the head.


A lethal birth defect in which most of the brain and parts of the skull are missing; absence of the encephalon.


A neurological disorder in which the person affected has an abnormally small head due to a failure of brain growth.


A defect in brain development resulting in small or missing brain hemispheres


An abnormally small head and underdeveloped brain


What is microcephaly?

Microcephaly is a condition where a baby’s head is significantly smaller than normal.

What causes anencephaly?

Anencephaly can be caused by genetic and environmental factors, including folic acid deficiency.

Can anencephaly be detected before birth?

Yes, anencephaly can often be detected through prenatal ultrasound.

What are the causes of microcephaly?

Causes include genetic factors, infections during pregnancy, and environmental toxins.

Is there any treatment for anencephaly?

There is no cure for anencephaly; care focuses on comfort for the newborn.

Can anencephaly be prevented?

Adequate folic acid intake during pregnancy can reduce the risk of anencephaly.

Are there different types of microcephaly?

Yes, microcephaly can be primary (present at birth) or secondary (developing after birth).

How is microcephaly diagnosed?

Microcephaly is diagnosed by measuring the head circumference and comparing it to norms.

Can children with microcephaly develop normally?

Development varies; some may have normal intelligence, while others may have delays.

What is anencephaly?

Anencephaly is a condition where a baby is born without parts of the brain and skull.

What is the life expectancy for someone with microcephaly?

It varies; some live normal lifespans, while others may have complications.

What is the prognosis for anencephaly?

The prognosis is poor; infants usually do not survive long after birth.

Are there preventative measures for microcephaly?

Preventative measures include good prenatal care and avoiding harmful substances.

Do children with microcephaly require special care?

Many require lifelong care, depending on the severity of their condition.

What support is available for families with an anencephalic baby?

Support includes counseling, palliative care, and community resources.

Is there a genetic test for anencephaly?

While genetic factors play a role, there is no specific test for anencephaly.

How is microcephaly treated?

Treatment depends on the severity and may include supportive care and therapy.

Is anencephaly common?

Anencephaly is relatively rare, affecting about 3 in every 10,000 pregnancies.

How common is microcephaly?

Microcephaly is also rare but varies in frequency depending on the population and region.

Can microcephaly be detected in utero?

Yes, it can sometimes be detected through prenatal ultrasounds.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.

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