Birth defects of the brain, spine, or spinal cord. The two most common neural tube defects are spina bifida (when the spine does not close) and anencephaly (when part of the brain and skull are missing).1
1. Public Health Agency of Canada. Folic Acid and Neural Tube Defects [Internet]. 2018 [cited 2018 Nov 12]. Available from: https://www.canada.ca/en/public-health/services/pregnancy/folic-acid.html