Vitamin B12 deficiency in pregnancy may be associated with up to 5 times the risk of having babies with neural tube defects (NTD). You need to replace the deficient vitamin B 12 in form of oral capsule or injectable if there is associated low hemoglobin in mother. Vitamin B12, is essential for the normal functioning of nerve cells and red blood cells; synthesis and regulation of DNA, fatty acid; and other cell metabolisms in the body. Food derived from animals, such as poultry, fish, meat, milk and milk products, and fortified foods are a good source of the vitamin.