Anencephaly is absence of major part of skull, brain and scalp. It is a birth defect caused when the neural tube does not close as it should in third and fourth week of pregnancy. Neural tube normally closes during this period to form brain and spinal cord. Infant born with anencephaly has major part of brain missing.
Infant born with anencephaly are unconscious, blind and deaf. In fact the newborn is not viable. The condition is considered to be a lethal neural tube defect. Most fetuses are stillborn. Some infants born alive have rudimentary brain and they die within hours or days.
What Are The Causes Of Anencephaly?
The exact cause of anencephaly is not known. However, lack of folic acid in mother during the developmental stage of the fetus is suspected to be the underlying reason. Folic acid (vitamin B9) has major role to play in development of healthy neural tube which later on becomes brain and spinal cord. Its deficiency can increase the risk of neural tube defects, one such abnormality is anencephaly.
The other cause is certain drugs taken by the mother during pregnancy. Medicines for diabetes during pregnancy can increase the risk of anencephaly.There is no family history noted. However, if a woman has one child born with anencephaly, she may conceive other fetus with same condition at later stage.
The prevalence of anencephaly has decreased substantially as many women take folic acid supplementation prior and during their pregnancy. The actual prevalence is estimated to be 1 in 1000 pregnancies. In most cases it results in miscarriage.
Symptoms Of Anencephaly
When the neural tube does not close during the developmental stage of fetus, the brain is exposed to amniotic fluid that surrounds the fetus. It leads to degeneration of the brain and spinal cord tissue. As a result large part of brain, skull, and scalp skin does not develop. It can be termed as open skull.
In most cases there is miscarriage. If the baby is born it may have deformed brain and skull. The newborn is blind and deaf. The child is born unconscious and is not aware of the surrounding. He does not have any sensation of touch and pain. Babies born are usually dead or die within few hours after birth.
Diagnosis And Treatment Of Anencephaly
Anencephaly is easily detected during the routine ultrasound done during pregnancy. Several other tests help to confirm the diagnosis. This includes blood test which shows high level of alpha fetoprotein. It is the protein produced by fetal liver cells. This may be further confirmed with the help of amniocentesis which is an invasive procedure. In this procedure small amount of amniotic fluid is removed from the amniotic sac. The fluid is tested for alpha fetoprotein which is high if there is neural defect. All these procedures are performed between 14th and 18th months of pregnancy.
Anencephaly cannot be treated. However, if the child is born alive, all measures taken are supportive. The exposed area of brain is protected with special covering and instruments. The child is fed with a tube as it is difficult for him to swallow anything.
In recent times this condition has become lesser because woman who want to become pregnant often start taking folic acid supplementation before and during their pregnancy period. Besides supplementation, pregnant woman must also consume foods that are rich in folic content.