What are the signs of anencephaly?
Signs of anencephaly include:
- High levels of alpha-fetoprotein (a fetal protein) from a blood test or sample of amniotic fluid of the pregnant parent. This blood test is usually done in the second trimester of pregnancy.
- Too much fluid in the amniotic sac (polyhydramnios) may be seen during a prenatal ultrasound.
- Missing parts of the skull and brain.
- Exposed areas of brain tissue (no skin or skull covering it).
- Smaller head size than expected.
A healthcare provider will offer tests to detect conditions like anencephaly during pregnancy.
What are the symptoms of anencephaly?
The birthing parent may not be aware of any symptoms until a blood test or an ultrasound.
Newborns with anencephaly don’t have:
- Consciousness (awareness).
- Vision.
- Hearing.
- The ability to feel pain.
Not all newborns with anencephaly develop a brainstem. If they do, they may have reflexes and automatically respond to touch. Seeing your newborn respond like this might give you hope. But this isn’t a sign that they’re aware of your touch or that they’ll be able to live long-term with this condition.
What causes anencephaly?
A problem with how the neural tube forms and closes causes anencephaly. The neural tube is a flat piece of tissue that grows into a tube shape. Each part of the neural tube helps parts of a baby’s body grow:
- Brain and skull (top of the neural tube).
- Spinal cord (middle of the neural tube).
- Backbones (bottom of the neural tube).
Anencephaly happens when the top part of the neural tube doesn’t close during embryonic development. This occurs during the third and fourth week of pregnancy. The fetus continues to form, except the front of the brain (forebrain) and the top of the brain (cerebrum) don’t grow. Other parts of the brain may develop as expected but no skin or skull cover them.
Is anencephaly inherited?
As far as we know, anencephaly isn’t inherited (passed down in families). In most cases, it occurs without any family history of the condition (sporadic genetic mutation). But if you had a child with a neural tube defect (NTD) before, like spina bifida, you have a higher chance of having a baby with anencephaly. This risk is about 2% to 3 %, which is 20 times higher than in someone who hasn’t had a previous baby with spinal bifida.
What are the risk factors for anencephaly?
Certain medications and risk factors increase the chance of having a baby with anencephaly or another neural tube defect (NTD) including:
- Lack of folic acid: Not getting enough folic acid (vitamin B9) when you’re pregnant puts you at a higher risk of having a baby with anencephaly. A healthcare provider may recommend you take a prenatal vitamin with 400 micrograms (mcg) of folic acid before and during pregnancy.
- Diabetes: Changes to blood glucose levels (sugar in your blood) can be dangerous for a developing fetus. A healthcare provider can help you manage a diabetes diagnosis to reduce your risk of complications.
- Medications: Antiseizure medications such as phenytoin (Dilantin®), carbamazepine (Tegretol®) and valproic acid (Depakote®) can increase your risk of having a baby with NTDs. Some of these medications also treat migraines and bipolar disorder. Talk to your healthcare provider about the medications you currently take if you plan on becoming pregnant. Don’t stop taking medication unless your healthcare provider approves it.
- Opioid use: Taking opioids during the first two months of pregnancy can cause NTDs. Opioids may include heroin and prescription painkillers, such as hydrocodone.
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