Which of the following nutrient's inadequate intake in pregnancy leads to neural tube defects in fetus?

NIA - 29 January 2023

Obstetrics & Gynaecology

Easy

Appeared in: NIA - 29 January 2023

Explanation

Folic acid, a B-vitamin (B9), is essential for the synthesis of nucleic acids (DNA and RNA) and rapid cell division, which are critical processes during early embryonic development.
The neural tube closes between the 21st and 28th day after conception, often before a woman knows she is pregnant. Adequate folate levels are required during this specific window to ensure proper closure.
Failure of the neural tube to close properly results in severe and often fatal birth defects, primarily spina bifida and anencephaly.
Clinical evidence strongly supports that periconceptional folic acid supplementation can prevent 50-70% of neural tube defects.

Option A: Iron is vital for hematopoiesis (red blood cell formation) and oxygen transport. Its deficiency causes maternal anemia and is associated with low birth weight and preterm delivery, not neural tube defects.
Option C: Vitamin B12 cooperates with folate in DNA synthesis. While a severe deficiency might contribute to the risk, it is not the primary and most direct cause of NTDs. Folic acid deficiency is the main culprit.
Option D: Calcium is essential for the mineralization of fetal bones and teeth, particularly in the third trimester. It is not involved in the early neurological development of the neural tube.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Maternal nutrition and its impact on fetal development, specifically congenital anomalies as background academic context rather than a clinical decision trigger.
Nurses have a critical role in preconception counseling, educating all women of childbearing potential about the necessity of daily folic acid intake, as many pregnancies are unplanned.
During antenatal visits, nurses should assess for high-risk factors (e.g., history of a prior NTD, diabetes, anti-seizure medication use) that necessitate a higher dose of folic acid (4 mg/day).
Patient education should emphasize that supplementation must start before conception for maximum effectiveness, as the neural tube closes very early in gestation.

How to Approach the Question

First, identify the core concept of the question: a nutritional deficiency causing a specific birth defect.
The key terms are 'inadequate intake,' 'pregnancy,' and 'neural tube defects.'
This is a factual recall question. Access your knowledge about the specific roles of essential nutrients during pregnancy.
Directly link 'neural tube defects' to its well-known preventative nutrient, which is folic acid.
Briefly consider the other options to confirm they are incorrect. Iron is for blood, calcium is for bones, and Vitamin B12 has a secondary role to folate.
This process of elimination and direct association confirms that folic acid is the only correct answer.

Concept Tested & Keywords

Concept Tested: Maternal nutrition and its impact on fetal development, specifically congenital anomalies.
Stem keywords: inadequate intake, pregnancy, neural tube defects, fetus
Lead-in keywords: Which
Negative lead-in flag: false

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E6 Obstetrics Williams p. 81-95

E6 Biochemistry U Satyanarayana— Part 2 (pp 421-820 of 840) p. 139-141