About Anencephaly- Anencephaly is a rare and severe congenital birth defect in which a baby is born without parts of the brain and skull that normally develop during early pregnancy. It occurs when the neural tube, an embryonic structure that develops into the brain and spinal cord, fails to close properly. The condition can result in the absence of major portions of the brain, skull, and scalp. Because the brain and skull are essential for controlling vital body functions and supporting normal development, anencephaly is a life-limiting condition. Most babies affected by anencephaly are stillborn or die shortly after birth. Anencephaly develops very early in pregnancy, often before a woman knows that she is pregnant. It is generally not caused by anything the mother did during pregnancy.
The physical appearance of a baby with anencephaly can be noticeably different because portions of the skull and brain have not developed normally. Possible signs include:
Missing parts of the skull and scalp
Absence of portions of the brain, particularly the cerebral hemispheres
Abnormally formed facial features
Areas of exposed or incompletely covered tissue on the head
Abnormally folded or protruding brain tissue in some cases
Because of the severe brain abnormalities associated with anencephaly, an affected baby cannot develop normal consciousness or normal neurological functions. A baby born with anencephaly is generally unable to see, hear, or experience normal awareness of the surrounding environment. The ability to respond to stimuli and experience pain is also profoundly affected by the absence of normal brain structures.
The exact cause of anencephaly is not fully understood. It is believed to result from a combination of genetic, nutritional, and environmental factors. Anencephaly occurs when the neural tube fails to close during the early weeks of pregnancy. The neural tube normally closes very early in fetal development and later forms the brain and spinal cord.
One of the most important known factors associated with neural tube defects is insufficient folic acid (vitamin B9). Adequate folic acid before conception and during the early stages of pregnancy can substantially reduce the risk of neural tube defects, including anencephaly and spina bifida.
However, taking folic acid does not guarantee that anencephaly will not occur. The condition can develop even when a mother has taken appropriate supplements. Other factors that may contribute to neural tube defects can include:
Certain genetic factors
Previous pregnancy affected by a neural tube defect
Certain medications
Some maternal medical conditions
Nutritional deficiencies
Certain environmental factors
In many cases, no specific cause can be identified.
Anencephaly is not usually inherited in a simple pattern. Although genetic factors may contribute to the risk, most cases occur sporadically. Having a previous pregnancy affected by a neural tube defect can increase the likelihood of another affected pregnancy. Women with such a history should discuss future pregnancy planning and folic acid supplementation with their healthcare provider.
A prenatal ultrasound can identify characteristic abnormalities of the fetal brain and skull. Anencephaly may be detected during an early pregnancy ultrasound or during the routine second-trimester ultrasound examination.
Blood tests performed during pregnancy may also help identify an increased risk of neural tube defects. One important screening test measures alpha-fetoprotein (AFP) in the mother’s blood. Elevated AFP levels can be associated with neural tube defects, although an elevated result does not by itself establish a diagnosis.
Depending on the circumstances, the healthcare provider may recommend additional ultrasound examinations or other prenatal testing to confirm the diagnosis and assess the pregnancy.
Unfortunately, there is no treatment that can repair or replace the missing brain and skull structures associated with anencephaly. The condition cannot be cured before or after birth. When anencephaly is diagnosed during pregnancy, healthcare professionals discuss the diagnosis and available options with the parents. Care is individualized and may include continued pregnancy care, delivery planning, and perinatal or neonatal palliative care. If a baby is born alive, treatment generally focuses on keeping the baby comfortable and providing supportive care. The medical team may help manage feeding difficulties, breathing problems, temperature regulation, and other symptoms.
Anencephaly is considered a fatal congenital condition. Most affected pregnancies result in stillbirth, and babies who are born alive generally survive only for a short period. Rare cases of longer survival have been reported, but meaningful neurological development is not expected because of the extensive absence of brain structures. Healthcare professionals can provide parents with individualized information about the expected course based on the findings during pregnancy.
Not every case of anencephaly can be prevented, but adequate folic acid intake before pregnancy and during early pregnancy can significantly reduce the risk of neural tube defects. Because the neural tube develops and closes very early—often within the first month of pregnancy—it is important for people who may become pregnant to have adequate folic acid before conception, rather than waiting until pregnancy is confirmed. The appropriate folic acid dose can vary depending on an individual’s medical history and risk factors. People planning a pregnancy should discuss supplementation with their healthcare provider.
If a previous pregnancy was affected by anencephaly or another neural tube defect, the risk in a future pregnancy may be higher than in the general population. Before planning another pregnancy, it is advisable to consult a gynecologist or obstetrician. The healthcare provider can recommend an appropriate folic acid dose, review medications and medical conditions, and arrange suitable prenatal screening. Early prenatal care is particularly important in pregnancies with an increased risk of neural tube defects.
Contact your healthcare provider for regular prenatal care as soon as pregnancy is confirmed or when planning a pregnancy. If you have previously had a pregnancy affected by anencephaly or another neural tube defect, speak with your doctor before becoming pregnant again whenever possible. Your healthcare provider can discuss folic acid supplementation and appropriate prenatal screening.
Anencephaly is a severe congenital birth defect in which major portions of the brain and skull fail to develop normally because the neural tube does not close properly during early pregnancy.
Most babies with anencephaly are stillborn or die shortly after birth. Long-term survival is extremely rare, and normal neurological development is not expected.
Yes. Anencephaly can often be detected through prenatal ultrasound. Maternal blood screening, including AFP testing, may also help identify an increased risk of a neural tube defect.
The exact cause is usually unknown. A combination of genetic, nutritional, and environmental factors may contribute. Insufficient folic acid is an important known risk factor for neural tube defects.
Adequate folic acid before conception and during early pregnancy can significantly reduce the risk of neural tube defects. However, it cannot prevent every case.
There is an increased risk of a neural tube defect in a subsequent pregnancy if a previous pregnancy was affected. A doctor can provide individualized recurrence-risk counseling and recommend appropriate folic acid supplementation.
No. Both are neural tube defects, but they affect different areas. Anencephaly primarily affects development of the brain and skull, whereas spina bifida primarily affects development of the spinal cord and vertebrae.
Medical Disclaimer: This article is intended for general educational and informational purposes only. It should not be considered a substitute for professional medical advice, diagnosis, or treatment. If you are pregnant or have concerns about your baby’s development, consult a qualified healthcare professional.
