Importance of Folic Acid for Pregnant Women Folic acid is a water-soluble B vitamin that synthesizes cells in our body, keeps the body healthy and strengthens the immune system. However, for pregnant women, it has special significance. Pregnant women need to increase their folic acid intake because it can prevent developmental defects in the fetus. Folic acid is one of the most important nutrients during the early development of the fetal spine. In addition, folic acid can also increase the amount of oxygen transported, strengthen blood circulation, and reduce the occurrence of anemia.