MODEL RELEASED. Pregnant woman with vitamin tablets. A pregnant woman taking folic acid enriched multi-vitamin tablets. Folic acid has been shown to reduce the risk of pregnant women giving birth to children with spine or brain defects. The most common birth defects are known as neural tube defects, which affect the brain and spinal cord of the developing foetus. These defects can occur in the very first stages of pregnancy, therefore women of childbearing age are encouraged to include folic acid in their diets. Natural sources of folic acid include chicken liver, dark green vegetables such as collards, and dried beans and peas.