**Core Concept**
Folic acid supplementation is crucial during pregnancy to prevent neural tube defects (NTDs) in newborns. NTDs are congenital anomalies resulting from the incomplete closure of the neural tube, which forms the brain and spinal cord.

**Why the Correct Answer is Right**
Folic acid plays a pivotal role in DNA synthesis and repair, cell division, and growth. During embryonic development, folic acid is essential for the proper closure of the neural tube. The recommended daily dose of folic acid for pregnant women is 400-800 mcg to prevent NTDs, with a higher dose of 4,000 mcg recommended for women at high risk. Folic acid supplementation is most effective when taken before conception and continues through the first trimester of pregnancy.

**Why Each Wrong Option is Incorrect**
**Option A:** Vitamin A supplementation is not directly related to the prevention of neural tube defects. While vitamin A is essential for vision, immune function, and skin health, it does not have a role in neural tube closure.
**Option B:** Vitamin E is an antioxidant that protects cells from damage but does not play a role in preventing neural tube defects. Its primary functions include protecting cell membranes and supporting immune function.
**Option C:** Iron supplementation is crucial during pregnancy to prevent anemia but is not directly related to neural tube defect prevention. Iron is essential for the production of hemoglobin, which carries oxygen to tissues.

**Clinical Pearl / High-Yield Fact**
The American College of Obstetricians and Gynecologists (ACOG) recommends that all women of childbearing age consume 400-800 mcg of folic acid daily to prevent neural tube defects. This recommendation applies to all women, regardless of their family history or previous pregnancy outcomes.

**Correct Answer: C. Folic acid supplementation is crucial during pregnancy to prevent neural tube defects in newborns.