January is National Birth Defect Awareness Month. Here’s what we think you should know about Neural Tube Defects; a classification of potentially preventable birth defects.
First, what are Neural Tube Defects?
Neural tube defects (NTD) are abnormalities related to the development of the central nervous system and spine. They may be part of a genetic syndrome, or an individual abnormality. After heart defects, they are the most common major birth defect. In the United States, up to 1/5,000 developing infants have anencephaly (absence of part of the brain and skull) and 2/5,000 developing infants have spina bifida (gaps in the backbone that leave the spinal cord exposed). The part of the baby that makes up the central nervous system and spine begins to develop in the first few weeks after fertilization, sometimes before a woman knows she is pregnant. Some, but not all, NTDs can be prevented with proper health and nutrition before pregnancy and through the first trimester, but especially in the first month of pregnancy.
Now, here’s the why.
The risk of NTDs increases as a result of any, or a combination of factors. Racial, Ethnic, and Geographic differences are probably due to a combination of genetic predisposition, diet, and environmental factors.
- Genetic Predisposition
- Family History
- Ethnicity: In the United States, some studies have found higher rates of NTD in Hispanic or African-American Populations
- Genetics
- Chromosome Abnormalities: Trisomy 13, Trisomy 18, Triploidy (3 sets of chromosomes)
- Single gene defects: Hundreds of genes are likely involved in Neural Tube Closure and abnormalities in any of these may contribute to NTD
- Genes involved in folic acid pathway: (example: MTHFR mutation has been shown in some studies to be associated with increased NTDs, but not in others)
- Geographic Region
- NTDs were increased after exposure to a fungal neurotoxin found at the Texas-Mexico border.
- The Shanxi Province in China has the world’s highest rate of NTDs.
- Exposures
- Heat: High maternal body temperature such as fever, or hot tub/sauna use in the first trimester, especially the first month after fertilization has been shown to increase NTDs.
- Medications:
- Anti-seizure medications such as Valproic Acid, Phenytoin, and Carbamazepine.
- Anti-leukemia medications such as Aminopterin and Methotrexate
- Maternal Health:
- Diabetes, especially with poor glucose control
- Obesity
Why is Folic Acid important?
Multiple studies have shown that folic acid can reduce the risk of NTDs, but the way folic acid impacts neural tube development is not clearly known. Unfortunately, not all NTDs can be prevented by folic acid supplementation. In addition to eating a diet that has high folic acid, supplementation is recommended.
Here’s what a hopeful mother can do to reduce the risk for a Neural Tube Defect:
- Maintain a healthy weight
- If you are diabetic, maintain optimal glucose control
- Eat foods high in folic acid such as:
- Legumes
- Asparagus, Beets
- Leafy Green Vegetables, Brussels Sprouts, Broccoli
- Citrus Fruits, Papaya, Banana
- Nuts and Seeds
- Wheat Germ
- Avocado
- Avoid hot-tubs and saunas if you may be pregnant and for first trimester of pregnancy
- Begin supplemental folic acid at least 3 months before planned pregnancy and continue for at least the first trimester
- Low risk patients: recommend 400 mcg folic acid daily. At least this much is in most prenatal vitamins.
- High risk patients: recommend 4000 mcg (4mg) folic acid daily
While family planning can be important, seeking prenantal care early and being vigilant to attend all regularly scheduled visits is key for pregnant women. Screening for NTDs can be done by ultrasound in the second trimester. Depending on the findings, you may discuss a wide variety of management options with your obstetrician.
We hope we met your Eggspectations—An Eggspert
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Disclaimer: All of the comments on this page are for basic information only. They are based on the opinions and expertise of the authors and are not meant to provide a substitute for medical care or specific treatment recommendations. Each person is unique and requires individualized diagnosis and treatment plans. Any specific questions should be directed to your personal healthcare provider.