護理師評估一名 30 歲計畫懷孕的女性。應建議補充哪種營養素以預防胎兒神經管缺陷？

葉酸（Folic acid）是 DNA 合成與細胞分裂的必要營養素。在懷孕初期，葉酸對於胎兒神經管的閉合至關重要。研究證實，計畫懷孕的女性在受孕前與懷孕初期補充葉酸，能顯著降低胎兒發生神經管缺陷（如脊柱裂、無腦症）的機率。其他補充劑（如鐵、鈣、B12）雖對孕期健康重要，但並非預防神經管缺陷的特定關鍵營養素。

Folic acid is essential for DNA synthesis and cell division, playing a critical role in the proper closure of the fetal neural tube during early pregnancy. Supplementation before conception and during the first trimester is proven to significantly reduce the risk of neural tube defects such as spina bifida and anencephaly.