Neural tube defects
What is Neural tube defects?
Neural tube defects are birth conditions that happen when the neural tube does not close properly during early pregnancy. The neural tube is the structure in a developing baby that becomes the brain, spine, and spinal cord. When this tube does not seal completely in the first month of pregnancy, it can lead to serious conditions.
The most common types are spina bifida and anencephaly. Spina bifida occurs when the spinal column does not close all the way, leaving part of the spinal cord exposed. Anencephaly happens when most of the brain and skull do not develop. These conditions form between 21 and 28 days after conception, often before a woman knows she is pregnant.
Neural tube defects affect about 3,000 pregnancies in the United States each year. Early screening through blood tests can help identify pregnancies at higher risk. This allows parents and doctors to make informed decisions and plan appropriate care.
Symptoms
- Abnormal opening in the skull or spine visible on ultrasound
- Exposed tissue along the back or skull at birth
- Fluid-filled sac on the baby's back
- Weakness or paralysis in the legs after birth
- Bladder and bowel control problems in affected infants
- Hydrocephalus, which is excess fluid in the brain
- Difficulty with movement and sensation below the defect
Most neural tube defects are detected during pregnancy through screening tests and ultrasound imaging. Many babies with spina bifida survive with surgery and ongoing care. Sadly, anencephaly is always fatal, usually within hours or days of birth.
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Causes and risk factors
Neural tube defects happen when the neural tube does not close properly in the first few weeks of pregnancy. The exact cause is not fully understood, but genetics and nutrition both play important roles. Low levels of folate, also called folic acid or vitamin B9, are strongly linked to higher risk. Women who do not get enough folate before and during early pregnancy have a much greater chance of having a baby with these defects.
Other risk factors include a family history of neural tube defects, diabetes in the mother, obesity, and certain medications. Taking anti-seizure drugs during pregnancy can increase risk. Women who have already had one pregnancy affected by a neural tube defect have a higher chance of it happening again. High body temperature from fever or hot tub use in early pregnancy may also contribute to risk.
How it's diagnosed
Neural tube defects are diagnosed through prenatal screening and imaging tests. Blood tests during pregnancy measure alpha fetoprotein, or AFP, which is a protein made by the developing baby. High levels of AFP in the mother's blood can signal a neural tube defect. This screening is typically done between 15 and 20 weeks of pregnancy. Ultrasound imaging can then show the physical signs of spina bifida or anencephaly.
Rite Aid offers AFP testing through our add-on screening options. If you are pregnant or planning to become pregnant, AFP screening can help detect potential issues early. This allows you to work with your healthcare provider to plan the best care. After birth, neural tube defects are confirmed through physical examination and imaging studies.
Treatment options
- Folic acid supplementation before conception and during early pregnancy to reduce risk by up to 70 percent
- Prenatal surgery to close spinal defects before birth in some cases
- Surgery shortly after birth to close the opening and protect the spinal cord
- Shunt placement to drain excess fluid from the brain if hydrocephalus develops
- Physical therapy to help with mobility and muscle strength
- Assistive devices such as braces, walkers, or wheelchairs as needed
- Bladder and bowel management programs throughout life
- Regular monitoring by a team of specialists including neurologists and orthopedic surgeons
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Frequently asked questions
Neural tube defects are birth conditions that occur when the neural tube does not close properly during the first month of pregnancy. The neural tube develops into the baby's brain, spine, and spinal cord. When it does not seal correctly, serious conditions like spina bifida or anencephaly can result.
Neural tube defects affect about 3,000 pregnancies in the United States each year. The rate has decreased significantly since folic acid fortification of grain products began in 1998. With proper folic acid intake, the risk can be reduced by up to 70 percent.
The alpha fetoprotein test, or AFP test, measures a protein made by the developing baby. High levels of AFP in maternal blood between 15 and 20 weeks of pregnancy can indicate a neural tube defect. This screening test is followed by ultrasound imaging to confirm or rule out the condition.
Taking 400 micrograms of folic acid daily before conception and during early pregnancy can prevent up to 70 percent of neural tube defects. Women who have had a previous pregnancy affected by these defects should take a higher dose of 4,000 micrograms daily. Eating foods rich in folate and avoiding high body temperatures also help reduce risk.
Spina bifida occurs when the spinal column does not close completely, leaving the spinal cord partially exposed. Many babies with spina bifida survive with surgery and ongoing care. Anencephaly happens when most of the brain and skull do not develop, and this condition is always fatal within hours or days of birth.
Women with low folate levels, diabetes, obesity, or a family history of neural tube defects have higher risk. Those taking certain anti-seizure medications during pregnancy also face increased risk. Women who have already had one affected pregnancy are more likely to have another baby with the condition.
Neural tube defects develop very early in pregnancy, between 21 and 28 days after conception. This is often before a woman realizes she is pregnant. That is why it is so important to take folic acid before trying to conceive, not just after finding out you are pregnant.
Many people with spina bifida live full and active lives with proper medical care and support. The severity varies widely depending on where and how large the opening is. Some individuals need wheelchairs and extensive medical care, while others have milder symptoms and walk independently.
A high AFP level does not mean your baby definitely has a neural tube defect. Other factors can cause elevated AFP, including twins or incorrect dating of the pregnancy. Your doctor will order a detailed ultrasound and possibly amniocentesis to get more information and determine the cause of the high reading.
Yes, all women of childbearing age should take 400 micrograms of folic acid daily. Since neural tube defects form so early in pregnancy, often before you know you are pregnant, it is important to have adequate folate levels at all times. Most prenatal vitamins and many multivitamins contain the recommended amount.