Birth defects of the neural tube have serious effects on the baby’s development. Read more to understand how to detect them…
In a baby, the neural tube normally develops into the brain and spinal cord. It starts as a tiny, flat ribbon turning into a tube by the end of the first month of pregnancy. NTD is a birth defect that develops when the neural tube is absent, partially closed or left open during the 3rd week of pregnancy. There are two most common neural tube defects- Spina bifida and Anencephaly.
In Spina bifida, the fetal spinal column does not close completely causing paralysis of the legs due to nerve damage. Babies with anencephaly do not have a fully developed brain and skull and are usually either stillborn or die shortly after birth
How common are NTDs?
The overall pooled birth prevalence of NTD in India is 5 per 1000 total births.
What causes NTDs?
NTD is classified as a complex disorder, the exact cause for which involves a multitude of factors including genetics and environmental factors like certain pre-existing health conditions, inadequate levels of folic acid as well as intake of certain medications.
You are at greater risk of having a baby with NTD if you:
- Have obesity and poorly controlled diabetes
- Have a history of baby with NTD
- Have inadequate levels of folic acid in the body
- Are under anti-seizure medication
- Are exposed to high temperatures or develop a fever during the first 4 to 6 weeks of pregnancy
- Struggle with alcohol or drug use
Identifying NTD-affected baby before birth
Diagnosis of NTDs during pregnancy can be through a combination of laboratory and imaging tests like ultrasonography.
Prenatal ultrasound imaging:
It aids in identifying the possibility of almost all types of NTDs in the fetus.
Serum marker tests:
Serum screening tests like Triple or Quadruple marker test recommended in the second trimester, checks for levels of Alpha-Fetoprotein (AFP) which is the major serum protein in early embryonic life and is also involved in preventing fetal immune rejection. In presence of an open NTD condition, the AFP leaks into the amniotic fluid, through which it enters the bloodstream. Hence elevated levels of AFP are considered to be an indication of NTD in the fetus. Apart from AFP, other hormones measured in these tests include the Human Chorionic Gonadotropin (hCG), Estriol, Pregnancy-associated Plasma Protein-A (PAPP-A) and Inhibin- A levels of which in totality with the Nuchal Translucency measurement, age of the pregnant mother and weight aid in providing probable risk for other chromosomal aneuploidies like Trisomy 21 (Downs syndrome) and 18 (Edwards syndrome).
In case higher risk for NTD is detected through USG and serum screening, your healthcare provider will recommend a confirmatory diagnostic test that includes either- Amniocentesis or Chorionic Villus Sampling (CVS)
- Consult your healthcare provider for the best dose of supplements like folic acid before planning a pregnancy and during early pregnancy.
- Keep medical conditions like diabetes or obesity under control before you plan a pregnancy.
How can it be treated?
There is no cure for NTDs. Nerve damage and loss of function is present at birth and is usually permanent. However, a variety of management strategies can prevent further damage and help to cope up with complications.
“Getting tested? Why not PREVENTIVE CARE!”