Anencephaly

What is it?
Anencephaly is a fatal birth defect where the baby is born without parts of their brain and skull. This affects the baby’s nervous system, comprising their brain, spine, and nerves. In early pregnancy, the neural tube develops into the baby’s brain and spine, with the upper part helping form the brain and skull, the middle part forming the spinal cord, and the lower part forming the backbone. However with anencephaly, the upper portion of the neural tube doesn’t function as it should, resulting in this birth defect. When the top of the neural tube doesn’t close during embryonic development, around the third and fourth week of pregnancy, the fetus continues to form incompletely. The baby is often developed without the forebrain and cerebrum, the parts of the brain which are responsible for cognitive processes, hormone regulation, sensory processing, coordinating movement, and more (Anencephaly, n.d.). This usually results in a miscarriage or a stillborn baby–only about 25% of babies that develop anencephaly are born alive (Anencephaly, n.d.). Since this birth defect affects brain development, babies born with it usually live only a few minutes, hours, or days. (Anencephaly | Birth Defects, 2024)

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​https://www.fetalhealthfoundation.org/fetal-syndromes/anencephaly/

Causes
Not all causes of anencephaly are known, but there are many identified factors that can increase the baby’s chance of developing anencephaly. Prominent amongst these is the importance of folic acid for the baby’s development. Not getting enough folic acid (or vitamin B9) when pregnant puts you at higher risk of having a baby with anencephaly. Most healthcare providers will recommend you take prenatal vitamins of folate to reduce the risk of anencephaly. Diabetes and other health conditions that are not well managed can also increase your risk. Changes to the glucose level in your blood (such as those brought on by diabetes) can be dangerous for a fetus. Certain medications and opioids also can cause neural tube defects. Antiseizure medications such as phenytoin, carbamazepine, and valproic acid, in addition to certain medicine made to treat bipolar disorder and migraines and opioids such as heroin and prescription painkillers (hydrocodone), all increase your risk of developing anencephaly. Be sure to talk to a doctor or healthcare provider if you are taking any of these. Finally, overheating may also increase your risk of developing this defect, which includes things like fevers, getting into a hot tub, etc. (Anencephaly: What It Is, Causes, Signs & Prevention, n.d.)

Diagnosing
Many prenatal tests administered to check up on the health of the baby can sense anencephaly. The quad marker screen, a blood test that checks on neural tube defects and other genetic conditions, requires drawing a sample of the pregnant parent’s blood and sending it to a lab where it is tested for four markers. One of these markers, the alpha-fetoprotein (AFP), tests for high levels of protein in the blood, which is leaked into the parent’s bloodstream if anencephaly is present in the fetus. An ultrasound test can also confirm this, which requires taking images of the fetus in the womb (a sonogram) and checking for defects in the skull, brain, and spine. Similarly, a fetal MRI (magnetic resonance imaging) uses high power magnets to take a closer look at the fetus’ brain and spine, providing detailed images of tissues and bones. Finally, amniocentesis requires a thin needle being inserted into the amniotic sac (the bubble around the fetus) and withdraws some fluid, which can then be tested for high levels of AFP and an enzyme called acetylcholinesterase. A higher presence of either of these would indicate a neural tube defect in your fetus. (Anencephaly: What It Is, Causes, Signs & Prevention, n.d.)

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​https://www.lumen.luc.edu/lumen/meded/radio/curriculum/obgyn/anencephaly.htm

Preventative Behaviors
Although it may not be possible to completely eliminate your chances of having a child with anencephaly, there are many things you can do to greatly reduce your risk. Consume plenty of folic acid, even if attempting to get pregnant, as having plenty of folate in the first months is the most crucial. Discuss any medication you may be on with a healthcare provider to discuss their likelihood of increasing your chances of developing a neural tube defect. Finally, and the most important, is managing your health. As the parent, your health is vital for your fetus’ health. This dependance is important for your fetus to grow and thrive, so make sure your health is being managed (especially if you have diseases such as diabetes).


Works Cited
Anencephaly. (n.d.). Boston Children's Hospital. Retrieved June 25, 2024, from https://www.childrenshospital.org/conditions/anencephaly
Anencephaly. (n.d.). Fetal Health Foundation. Retrieved June 25, 2024, from https://www.fetalhealthfoundation.org/fetal-syndromes/anencephaly/
Anencephaly | Birth Defects. (2024, May 16). CDC. Retrieved June 25, 2024, from https://www.cdc.gov/birth-defects/about/anencephaly.html
Anencephaly: What It Is, Causes, Signs & Prevention. (n.d.). Cleveland Clinic. Retrieved June 25, 2024, from https://my.clevelandclinic.org/health/diseases/15032-anencephaly

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