Inadequate intake by the pregnant woman of which vitamin can cause neural tube defect?

AIIMS Nagpur NO- 2020

Obstetrics & Gynaecology

Easy

Appeared in: AIIMS Nagpur NO- 2020

Explanation

Folic acid, also known as Vitamin B9, is essential for the synthesis of nucleic acids (DNA and RNA) and the metabolism of amino acids, which are critical for rapid cell division and growth.
During early embryonic development (weeks 3-4 of gestation), the neural tube forms and closes to become the brain and spinal cord.
Insufficient maternal folate levels during this critical period can lead to failure of the neural tube to close, resulting in defects like spina bifida (an open spine) or anencephaly (absence of a major portion of the brain).
Because this closure happens before many women realize they are pregnant, public health guidelines recommend that all women of childbearing potential take a daily folic acid supplement of 400 micrograms (0.4 mg).

Option A: Niacin (Vitamin B3) deficiency causes pellagra, a systemic disease with symptoms often remembered by the '3 Ds': dermatitis, diarrhea, and dementia. It is not associated with neural tube defects.
Option C: Thiamine (Vitamin B1) deficiency leads to beriberi, which affects the cardiovascular system (wet beriberi) and/or the nervous system (dry beriberi). In chronic alcoholism, it can cause Wernicke-Korsakoff syndrome. It does not cause neural tube defects.
Option D: Riboflavin (Vitamin B2) deficiency, known as ariboflavinosis, presents with symptoms like sore throat, inflammation and cracks at the corners of the mouth (cheilosis), and a swollen, magenta-colored tongue (glossitis). It is not linked to neural tube defects.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Role of vitamins in pregnancy and prevention of birth defects as background academic context rather than a clinical decision trigger.
Nurses have a crucial role in preconception counseling, educating all women of reproductive age about the importance of daily folic acid supplementation to prevent NTDs.
This education should emphasize that supplementation needs to start before conception for maximum benefit, as the neural tube closes very early in pregnancy.
Food fortification programs (e.g., adding folic acid to flour and cereals) have significantly reduced the incidence of NTDs, but supplementation remains essential to ensure adequate intake.

How to Approach the Question

This is a factual recall question common in nursing and health sciences.
First, identify the key terms in the question: 'inadequate intake,' 'pregnant woman,' and 'neural tube defect.'
The primary task is to link the specific congenital anomaly (neural tube defect) to the correct vitamin deficiency.
Recall fundamental knowledge about prenatal nutrition. The connection between folic acid and the prevention of spina bifida and anencephaly is a cornerstone of prenatal care.
Systematically evaluate the other options. Recall the classic deficiency diseases for each: Niacin causes Pellagra, Thiamine causes Beriberi, and Riboflavin causes Ariboflavinosis.
Since none of the other options are related to fetal neural development, you can confidently select Folic acid.

Concept Tested & Keywords

Concept Tested: Role of vitamins in pregnancy and prevention of birth defects
Stem keywords: inadequate intake, pregnant woman, vitamin, neural tube defect
Lead-in keywords: which vitamin
Clinical cues: Age/sex group narrows the expected diagnosis, intervention, or normal reference range.

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E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 1367-1369

E6 Obstetrics Williams p. 81-95