What is anencephaly?
Anencephaly is a serious birth condition where parts of the baby’s brain and skull do not develop properly. It is a type of neural tube defect (NTD). The condition happens very early in pregnancy, often before the mother even knows she is pregnant.
In the early stages of pregnancy, the nervous system of the developing baby starts as a single structure called the neural plate. By day 28 of pregnancy, the neural plate should fold over and close to form the neural tube. If the neural tube does not close completely, it results in a neural tube defect (NTD) such as anencephaly.
We screen for anencephaly at the 20-week scan (between 18+0 to 20+6 weeks of pregnancy). However, it is often noticed during the scan at around 12 weeks of pregnancy. Ultrasound shows the absence of a large portion of the brain and skull. The baby’s face and neck may also be affected.
We do not know exactly what causes anencephaly. It is not caused by something you have or have not done. It can happen due to a combination of genetic and environmental factors. A lack of folic acid before and during early pregnancy increases the risk.
Anencephaly happens in about 5 babies out of every 10,000 (0.05%).
Babies with anencephaly do not survive. Most are stillborn or die shortly after birth. The condition is not treatable.
You will be offered time to talk to specialists. Some parents choose to continue the pregnancy and receive support through palliative care. Others may consider ending the pregnancy. This is a very personal decision, and support is available for you whichever path you take (see link below to Antenatal Results and Choices)
There is a small increased risk in future pregnancies. Taking folic acid (5mg daily) before and in early pregnancy can help reduce this risk.