Prenatal Diagnosis
Prenatal diagnosis is most commonly carried out using screening methods such as maternal serum screening tests, including Maternal Serum Alpha-Fetoprotein (MSAFP) screening performed during the second trimester (16–18 weeks of gestation), as well as fetal ultrasound. The MSAFP screen measures the level of alpha-fetoprotein (AFP), a protein that is naturally produced by the fetus and placenta. During pregnancy, a small amount of AFP normally crosses the placenta and enters the mother’s bloodstream. If abnormally high levels of this protein appear in the mother’s bloodstream, it may indicate that the fetus has an ‘open’ (not skin-covered) neural tube defect.
The MSAFP test, however, is not specific for spina bifida and requires correct gestational dates to be most accurate; it cannot definitively determine that there is a problem with the fetus. Amniocentesis may also be used to diagnose spina bifida and may be followed by prenatal genome sequencing when a genetic cause is suspected. Although amniocentesis cannot reveal the severity of spina bifida, finding high levels of AFP and other proteins may indicate that the disorder is present.
Postnatal Diagnosis
Mild cases of spina bifida (occulta, closed) not diagnosed during prenatal testing may be detected postnatally by plain film X-ray examination. Individuals with the more severe forms of spina bifida often have muscle weakness in their feet, hips, and legs that result in deformities that may be present at birth. Doctors may use Magnetic Resonance Imaging (MRI) or a Computed Tomography (CT) scan to get a clearer view of the spinal cord and vertebrae. If hydrocephalus is suspected, the doctor may request a CT scan and/or X-ray of the skull to look for extra cerebrospinal fluid inside the brain1.
References:
- https://www.ninds.nih.gov/disorders/spina_bifida/detail_spina_bifida.htm
- https://www.cdc.gov/ncbddd/spinabifida/facts.html
- Bhide, P; Sagoo, GS; Moorthie, S; Burton, H; Kar, A (July 2013). “Systematic review of birth prevalence of neural tube defects in India.”. Birth defects research. Part A, Clinical and molecular teratology 97 (7): 437–43.
- Kondo, A; Kamihira, O; Ozawa, H (January 2009). “Neural tube defects: prevalence, etiology and prevention.”. International journal of urology: official journal of the Japanese Urological Association 16 (1): 49–57.
- https://ghr.nlm.nih.gov/condition/spina-bifida
