Which of the following vitamin deficiencies in pregnancy leads to spina bifida in the foetus?

DSSSB 14 August 2024

Obstetrics & Gynaecology

Easy

Appeared in: DSSSB 14 August 2024

Explanation

Folate, also known as Vitamin B9, is essential for the synthesis of DNA and RNA, which is critical for cell division and growth.
During early embryonic development, folate plays a crucial role in the formation and closure of the neural tube, the structure that develops into the brain and spinal cord.
The neural tube closes between the 3rd and 4th week after conception, a period when many women may not yet be aware they are pregnant.
A deficiency in folate during this critical window prevents the neural tube from closing properly, leading to neural tube defects (NTDs) like spina bifida (an open spine) and anencephaly (absence of a major portion of the brain).
This direct link is why folic acid supplementation is universally recommended for women of childbearing age.

Option A: Tocopherol (Vitamin E) is a fat-soluble antioxidant. Its deficiency is not associated with the development of neural tube defects.
Option B: Niacin (Vitamin B3) deficiency causes pellagra, a systemic disease characterized by the '3 Ds': dermatitis, diarrhea, and dementia. It does not cause spina bifida.
Option D: Riboflavin (Vitamin B2) is vital for energy production. A deficiency, known as ariboflavinosis, leads to symptoms like sore throat, cheilosis (cracks at the corners of the mouth), and glossitis, but not neural tube defects.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain The role of vitamin deficiencies in causing congenital fetal anomalies as background academic context rather than a clinical decision trigger.
Preconception counseling is a critical nursing role. All women of childbearing age should be advised to take 400 mcg of folic acid daily, as nearly half of all pregnancies are unplanned, and neural tube closure occurs before many women know they are pregnant.
Nurses must educate patients about dietary sources of folate, including fortified grains (bread, pasta, rice, cereal), leafy green vegetables, beans, and citrus fruits, to complement supplementation.
Patient education should emphasize that while liver is a rich source of folate, it should be consumed with caution or avoided in early pregnancy due to its high vitamin A content, which can be teratogenic in large doses.

How to Approach the Question

First, identify the key terms in the question: 'vitamin deficiency', 'pregnancy', and 'spina bifida'.
Recognize that spina bifida is a type of neural tube defect (NTD), a major congenital anomaly.
Recall or deduce the specific vitamin directly linked to the prevention of NTDs. This is a foundational concept in prenatal care.
Evaluate each option. Folate (folic acid) is widely known for its role in preventing spina bifida.
Eliminate the other options by recalling the primary deficiency diseases associated with them: Tocopherol (Vitamin E) deficiency is rare and causes neurological issues; Niacin (Vitamin B3) deficiency causes pellagra; Riboflavin (Vitamin B2) deficiency causes ariboflavinosis.
Confirm that Folate is the only vitamin listed whose deficiency is a direct cause of spina bifida.

Concept Tested & Keywords

Concept Tested: The role of vitamin deficiencies in causing congenital fetal anomalies.
Stem keywords: vitamin deficiencies, pregnancy, spina bifida, foetus
Lead-in keywords: Which
Negative lead-in flag: false

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E6 Medicine Davidson Principles Practice 24e p. 735-737

E6 Obstetrics Williams p. 81-94