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Indian Pediatr 2010;47:
361-362 |
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Vitamin B Supplementation to Prevent Neural
Tube Defects? |
V Latha and M Sridhar,
Apollo Childrens Hospital, 15 Shafee Mohammed Road,
Thousand Lights, Chennai 600 006, India.
Email: [email protected]
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Periconceptional folic acid is recommended for preventing neural tube
defects(NTD)(1). Reports suggest that supplementation with vitamin B 12
is also necessary for the purpose(2). We present 2 patients with NTD,
where the mothers had evidence of vitamin B12 deficiency.
Case 1. A 5-month-old boy presented with
significant pallor and poor feeding. He was born to a 29-year-old mother
with history of previous 5 abortions (3 with fetal anomalies) and one
early neonatal death. She had received supplements of folic acid 5 mg once
daily before conception and continued through pregnancy. The baby,
delivered at full term, had a lumbar meningomyelocele that required
surgery. The patient’s hemoglobin was 3g/dL, and the mother’s hemoglobin
was 9 g/dL. Their peripheral smear showed macrocytic normochromic anemia.
Vitamin B 12 levels in the
mother and baby were 136 pg/mL and 47 pg/mL, respectively (normal 200-950
pg/mL); blood levels of folate were normal. The mother was a strict
vegetarian with low intake of vitamin B12.
Case 2. A gravida 5, para 3 mother with 2
miscarriages and two live children, delivered a boy at 35 weeks by
cesarean section, the indication being severe maternal anemia (hemoglobulin
level 5.1 gm/dL) and identification of a NTD in the fetus. Peripheral
smear showed macrocytic normochromic anemia, vitamin B 12
deficiency (86 pg/mL), and normal blood levels of folate and ferritin. The
baby had a thoraco-lumbo-sacral meningomyelocele, which needed surgical
intervention soon after birth. There was no history of previous NTD in the
family.
In both these cases, the newborn had a neural tube
defect, despite maternal folate supplementation and normal serum folate
level. Both mothers were however deficient in vitamin B 12.
Vitamin B 12
is found in foods from animals (fish, meat, poultry, eggs, milk and milk
products) and its deficiency is proposed as a cause of NTD(2,3).
Supplementation with folic acid, as in the present cases, did not prevent
the occurrence of the defects.
A large proportion of Indian population can be
classified as vegetarian with dietary exclusion of all animal products.
The precise role of maternal vitamin B 12
deficiency in occurrence of congenital anomalies and/or recurrent
abortions need to be examined. Mechanisms and preventive effect of vitamin
B12 supplementation also needs to be studied.
References
1. Wilson RD, Davies G, Désilets V, Reid GJ, Summers A,
Wyatt P, et al. The use of folic acid for the prevention of neural
tube defects and other congenital anomalies. J Obstet Gynaecol Can 2003;
25: 959-973.
2. Steen MT, Boddie AM, Fisher AJ, Macmahon W, Saxe D,
Sullivan KM, et al. Neural tube defects are associated with low
concentrations of cobalamin (vitamin B12) in amniotic fluid. Prenat Diagn
1998; 18: 545-555.
3. Godbole K, Deshmukh U, Yajnik C. Nutrigenetic determinants of neural
tube defects in India. Indian Pediatr 2009; 46: 467-475.
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