Anencephaly is a neural tube abnormality that occurs when the neural tube closure is incomplete during the embryonic period due to genetics and many harmful factors in the environment. Environmental factors, such as poisons and high doses of radiation that act directly or indirectly on the embryo, especially in the third and fourth weeks of life, can cause malformations in the development of the fetus. Colds, high fever or viral or bacterial infections during the early embryonic period can also cause embryonic death or various types of birth defects, including anencephaly. Neural tube malformations can also occur if certain medications are taken during pregnancy, such as high doses of hormonal and antitumor drugs. Folic acid deficiency can also cause neural tube malformations. It is recommended that oral folic acid of 0.4 mg per day be taken 3 months prior to pregnancy preparation and 3 months after pregnancy to prevent neural tube malformations in the fetus.