What is anencephaly?
Anencephaly is a neural tube defect that affects the brain, skull and spinal cord of a newborn. The defect results in the absence of portions of the brain and skull. The condition varies from individual to individual, in some the frontal area of the brain may be missing, in others the cerebrum may be missing, or both may be absent. In addition to the absence of significant amounts of brain tissue, the cranium, the bony covering of the skull that forms to protect the brain, is also largely absent.
How Common Is Anencephaly?
According to the Centers For Disease Control, an accurate number of cases in the United States is difficult to calculate due to several factors. Many anencephalic fetuses result in miscarriages, while other parents may choose to terminate the pregnancy when they are made aware of the diagnosis. Approximately 75% of all pregnancies carried to term or nearly to term result in a stillbirth. Overall, it is estimated that 1 in 1,000 pregnancies results in an anencephalic fetus, while approximately 1 in 10,000 live births have the condition. Rates of all neural tube defects are higher in countries that do not supplement the food supply with folic acid, and in places where malnutrition is common.
Can Anencephaly Be Prevented?
There are ways to minimize the risks of anencephaly; however, there is no absolute way to prevent it. Even with no risk factors, appropriate diet and supplementation, there is a risk of neural tube defects that cannot be removed.
Folic acid before and during pregnancy can reduce the risk of all neural tube defects. Many doctors recommend that women of child bearing age who are sexually active take folic acid routinely, as neural tube defects develop in the first few weeks of pregnancy, well before most women are aware they are pregnant.
Refraining from smoking and drinking alcohol can reduce the risk of the vast majority of birth defects, including neural tube defects.
Risk Factors For Anencephaly
- Families with a history of neural tube defects, such as a previous anencephalic pregnancy, spina bifida, encephalocele, hydranencephaly have a higher risk of neural tube defects than the general population.
- Too little folic acid in the mother’s diet
Research indicates that the following may play a role in anencephaly, but there is too little data to come to a conclusion:
Diagnosis of Anencephaly
The diagnosis of anencephaly may be made prior to birth, using ultrasound or lab testing of amniotic fluid. The defect is typically found after twelve weeks gestation during a routine ultrasound examination. Once there is a suspicion of a severe neural tube defect, lab work can be performed on amniotic fluid to confirm the diagnosis. Most women are aware that the fetus they are carrying is anecephalic prior to the birth.
At birth, if the condition was not previously diagnosed, the appearance of the newborn quickly leads to diagnosis, as the head is lacking the bone that typically makes up the forehead, top and back of the skull. The part of the head where the skull would typically be covering and protecting the brain is sunken, and only covered by skin.
Newborns with anencephaly may have additional issues, including additional missing bones in the face and head, a cleft palate, heart defects and issues with the soft tissues of the ears.
Prognosis For Anencephaly
There is no treatment for anencephaly. Medical care consists of supporting the newborn, not attempting to improve the condition. This lack of brain tissue is not compatible with life, as the body is unable to maintain routine functions, such as breathing independently. Approximately three out of four anencephaly pregnancies result in a stillbirth, the remaining cases result in a survival of hours or days.
The newborns who do survive for a short time after birth may be placed on a ventilator and require ICU level care for support. In many cases, the family opts for hospice care for the patient as ICU care does not change the long term outcome, which also provides the family with support during this very difficult time.
Many hospitals strive to support the family through by providing counseling, an opportunities to hold the baby, take photographs and
Organ Donation and Anencephaly
The vast majority of organ donation is done after a patient is pronounced brain dead. When the brain is no longer able to function, a series of clinical exams is done to determine that brain death has occurred and confirm that the patient is brain dead. Anencephalic newborns rarely progress to brain death. However, anencephalic newborns are often eligible to become donors through another type of organ donation, called donation after circulatory death, also known as donation after cardiac death (DCD).
In addition, it may be possible to donate tissue such as heart valves, or the liver for hepatocyte transplant (the liver tissue is processed before transplant, rather than the organ being transplanted whole), after cardiac death. Each case depends on the individual patient and family. Some families seek out organ donation, knowing that helping another child will help with their grief process. Other families choose not to participate during a time of great stress and sadness, and do not want to take the chance that the donation may not be possible after the birth. There is no right answer for everyone.
While one anencephalic newborn might be able to be a donor, another may not. Stillborn patients are unable to donate tissue or organs, while the newborn that survives for several hours may be able to become a donor.
The process often begins prior to the birth, with the arrangements made for donation ahead of time. It is important that parents remember that these preparations may not result in donation, yet it is often important to families who want donate that they make the attempt knowing that the effort may fruitless.
Parents who are aware that their fetus is anencephalic and would like to consider donation can work through their local organ procurement agency or tissue bank to determine if the process is something they would like to participate in. This can be arranged through the hospital where the delivery will take place or by contacting the organizations directly.
Your local organ procurement agency can be located using the HRSA website here: http://opotxfind.hrsa.gov/Search_OPO_OTC.aspx
A list of resources and support groups for families who have experienced anencephaly is located at http://anencephaly.net
Facts About Anencephaly. Centers For Disease Control. Accessed October, 2012. http://www.cdc.gov/ncbddd/birthdefects/Anencephaly.html