Folic acid (vitamin B9) deficiency during pregnancy can result in a baby born with defects in the brain or spinal cord. The worst version of these defects is anencephaly, where the baby is born without part of its brain and skull, and dies. The most common birth defect after folic acid deficiency during pregnancy is Spina Bifida. This occurs when part of the baby's spinal cord remains outside the body. The baby may have paralyzed legs and, later, may develop bladder and bowel control problems.
