Folic Acid Protection in Congenital Neural Tube Defects: A Narrative Review

Introduction: Neural tube defects, a congenital malformation of multifactorial source, affect more than 200,000 to 300,000 births a year, and are twice as common in developing countries. Food fortification with folic acid has been shown to be effective reducing this congenital malformation. The aim of this study was to look for evidence on the efficacy, interval and best dose of folic acid to be administered in the prophylaxis of neural tube defects.

Methods: Narrative literature review, using the PubMed database, available at: https://pubmed.ncbi.nlm.nih.gov/, using the keywords "Folic Acid and Pregnancy and Neural Tube", and applying the filters "Systematic review" and "last five years". Two researchers independently selected articles on the effects of folic acid in preventing neural tube birth defects. After reading the titles and abstracts, 11 of the 21 articles selected were read in full and all were included in the review. Another nine articles obtained from the PUBMED database, using the same keywords and published in the year 2023, were included to discuss the synthesis of the data.

Synthesis of the Data: Neural tube defects were associated with family history, previous stillbirth, unplanned pregnancy, stress during the periconceptional period, lack of prenatal care, use of alcohol, tobacco and exposure to medicines, pesticides, maternal age over 35, chronic maternal illness and low schooling. No evidence of side effects was found as to the supplementation with folic acid. Daily supplementation with 400-800μg, starting 1.5 months before conception and lasting 4 months, prevented the occurrence of neural tube defects and dietary supplementation with folic acid reduced the occurrence of the disease.

Conclusion: Current evidence indicates that folic acid supplementation for pregnant women, starting at 1.5 months before conception and lasting for 4 months, protects against congenital neural tube defects.