Anencephaly

Anencephaly is a birth defect characterized by a lack of skull formation so that what parts of the brain are still present are exposed to the open air. Much of the problem occurs in the third and fourth week of pregnancy when the brain and spinal cord are forming as part of the neural tube. The neural tube is a narrow channel that becomes a tube from embryonic tissue. The upper part of the neural tube fails to close so that parts of the brain, spinal cord and skull fail to form. The infant is born without the thinking parts of the brain so the baby is in effect born in a coma. Some infants are born without a brainstem and these infants die immediately after death because they cannot breathe.

Anencephaly is a common neural tube defect, affecting 1 out of 10,000 births. It occurs very early in the development of the embryo. The exact number of pregnancies resulting in anencephaly is not clear because many result in miscarriage before they can be identified. Having an infant born with anencephaly means that you are more likely to have another infant with the condition.

Infants with anencephaly are born deaf, blind, unconscious and with an inability to feel any kind of pain. They cannot ever grow a functioning cortex so these symptoms persist until death. Some die in utero; some die at birth; and some die within weeks after birth.

The cause of anencephaly is unknown. It is believed that a low maternal folate level is related to neural tube defects, including anencephaly. There may be other causes of anencephaly that are not completely clear. The addition of folate to the diet seems to reduce the incidence of these types of neural tube defects. This is why women should take in at least 0.4 mg of folic acid daily during their reproductive years. It is not believed that a genetic defect results in anencephaly so it is considered a purely environmentally caused disease.

Symptoms of neural tube defects resulting in anencephaly include the absence of the complete skull, the absence of the cerebral hemispheres and cerebellum of the brain, heart defects and an abnormal facial feature typical of the disease.

Doctors can test for anencephaly by doing an ultrasound that shows a lack of a skull and brain. There may be polyhydramnios or a condition of too much fluid inside the uterus. An amniocentesis can show an increased level of alpha-fetoprotein or can show an elevated urine estriol in the mother's urine. A pre-pregnancy folic acid will show those who are at risk of developing neural tube defects.

Anencephaly has no particular treatment and no cure. Some parents elect to have no medical treatment done on the baby, including no feeding and can then just spend time with their infant until it dies. Other parents choose to have feeding tubes placed to feed the baby but have no other treatment done. Still other parents want everything done to save their baby, but this is not recommended due to the prognosis of the infant.

The prognosis of babies with anencephaly is extremely poor. Many die in utero and are stillborn or result in miscarriage at some point in the pregnancy. If the baby is not stillborn, it cannot eat without a feeding tube, which is not recommended because it only prolongs death. The babies can die within a few hours, within a few days or, in rare cases, within a few weeks or months after birth. There is no hope of growing a brain so the infant always is without a forebrain or cerebellum.