Why should you take folic acid supplements before pregnancy? During pregnancy preparation, in addition to paying attention to diet and nutrition, preparing your mentality and lifestyle, supplementing folic acid is also essential. Folic acid is a B vitamin that plays a vital role in fetal neural tube development. If a pregnant woman is deficient in folate, adverse neural tube defects can result. In addition, some studies have found that folic acid can reduce the risk of fetal malformations such as heart and cleft lip.