Neural tube defects (NTDs) are the name of a group of birth defects involving the brain and spine. These can develop in the first 42 days of gestation and can affect the mental and physical development of a baby once born. There are three main defects that can occur before you even realise you may be pregnant. The chances of your baby developing a neural tube defect if you have no family history, are approximately 0.1 - 0.2%, although this can vary depending on where you live and your race. If a couple has had a child with a neural tube defect, their chances of having another child with any of the three types of neural tube defects increase to around 3%. This means that there is about a 97% chance that a neural tube defect will not occur in future pregnancies. With the number of cases of NTDs increasing, it’s even more prevalent that couples hoping to get pregnant learn what they are and how to prevent it occurring.
Spina Bifida
can occur when a baby's spine does not form properly. Part of the spinal cord may form outside of the vertebrae and is often not properly formed. This can lead to varying degrees of muscle weakness, paralysis, loss of sensation in the legs, and/or poor bladder and bowel control. Some babies with spina bifida also develop fluid on the brain (hydrocephalus) which can occasionally cause brain damage.
Anencephaly
is a neural tube defect where the top part of a baby’s skull and brain fail to form properly. Pregnancies where the baby has developed Anencephaly, may, unfortunately, be miscarried, stillborn, or die very shortly after birth.
Encephalocele
is a less common neural tube defect, which occurs when part of a baby's skull does not form properly, allowing part of the brain to grow outside of the skull. Babies with this type of neural tube defect do not tend to survive. Babies who do survive may have long term physical and mental handicaps, as well as a short life span.
One of the main causes of a baby developing an NTD is lack of a vitamin called folic acid [link to Folic Acid article] (folate) when the neural tube is forming at around 42 days after conception. Even if a woman eats well and does everything she can to have a healthy baby, there could still be a lack of folic acid in her body. Some women and babies may have a higher need for folic acid, and there is currently no way to tell who they are prior to pregnancy. Therefore it is recommended that women begin taking Folic Acid supplements up to a year before conception to bring their levels of folate up.
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Other risk factors that could cause a neural tube defect, include mothers having insulin-dependent diabetes and certain medications which may be used to control maternal epilepsy. It has also been identified that elevations in a woman's body temperature when the neural tube is forming, either from a high fever when ill or prolonged exposure to hot tubs or saunas.
Women must consume folic acid before she knows she is pregnant and up to a year before conception if you are actively trying for a baby, as the brain and spinal cord may have already begun to form by the time of your 12-week scan. The most effective way to prevent neural tube defects is to consume 400 mcg (or may be displayed as 400ug or 0.4mg) of folic acid daily at least one month prior to conception and throughout the first three months of pregnancy. If your BMI is 30 or above, a daily dose of 5 mg is recommended.