During pregnancy, deficiency of which of the following leads to Neural tube defect?

HPSSC - 2015

Obstetrics & Gynaecology

Easy

Appeared in: HPSSC - 2015

Explanation

Folic acid (a B-vitamin) is essential for the synthesis of nucleic acids (DNA and RNA) and for rapid cell division, which are critical processes during early embryonic development.
The neural tube, the precursor to the brain and spinal cord, forms and closes between the 21st and 28th day after conception.
A deficiency in folic acid during this critical period impairs cell proliferation and differentiation, leading to incomplete closure of the neural tube.
This failure of closure results in neural tube defects (NTDs) such as spina bifida (an open spine) and anencephaly (absence of a large part of the brain and skull).
Supplementation with folic acid before and during early pregnancy has been proven to reduce the incidence of NTDs by up to 70%.

Option A: Calcium is vital for the development of fetal bones and teeth and for maintaining maternal bone density. Its deficiency is associated with skeletal issues and an increased risk of preeclampsia, not neural tube defects.
Option B: Zinc is a trace element important for numerous enzymatic functions, immune system development, and overall fetal growth. While essential, its deficiency is not the direct cause of neural tube defects.
Option D: Iron is a key component of hemoglobin, necessary for oxygen transport in the blood. Iron deficiency leads to maternal and fetal anemia but is not linked to the formation of the neural tube.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Nutritional Deficiencies in Pregnancy as background academic context rather than a clinical decision trigger.
Preconception counseling is a critical nursing role. Nurses must educate all women of childbearing age about the importance of taking folic acid supplements daily, as nearly half of all pregnancies are unplanned.
Nurses should assess for high-risk factors for NTDs, such as a prior NTD-affected pregnancy, maternal diabetes, or use of certain antiepileptic medications (e.g., valproate, carbamazepine), which necessitate a higher dose of folic acid (4 mg/day).
Patient education should include dietary sources of folate (leafy green vegetables, legumes, fortified cereals), but it must be emphasized that supplementation is necessary to achieve the protective levels required to prevent NTDs.

How to Approach the Question

First, identify the core concept of the question, which is the link between a specific nutrient deficiency and a particular birth defect (Neural Tube Defect).
Recall the major roles of the nutrients listed in the options during pregnancy.
Calcium is primarily associated with bone health.
Zinc is linked to general growth and immunity.
Iron is crucial for preventing anemia.
Folic acid is widely known for its role in preventing neural tube defects.

Concept Tested & Keywords

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