The primary prevention of birth defects: Multivitamins or folic acid?

Area of Science:

• Obstetrics and Gynecology
• Public Health
• Genetics

Background:

• Periconceptional folic acid/multivitamin use prevents neural-tube defects.
• Evidence suggests benefits for other congenital abnormalities, but optimal dosage and formulation are debated.
• Previous studies show mixed results regarding folic acid alone versus multivitamins.

Purpose of the Study:

• To compare the efficacy of folic acid alone versus folic acid-containing multivitamins for preventing birth defects.
• To determine if high-dose folic acid (5 mg) is superior to standard doses (0.4-0.8 mg) in multivitamins.
• To analyze the impact of different supplementation strategies on specific types of congenital abnormalities.

Main Methods:

• Pooled analysis of two Hungarian randomized/controlled trials using multivitamins (0.8 mg folic acid).
• Comparison with data from the Hungarian Case-Control Surveillance of Congenital Abnormalities using high-dose folic acid.
• Statistical comparison of defect reduction rates between supplementation groups.

Main Results:

• Multivitamins (0.4-0.8 mg folic acid) showed greater reduction in neural-tube defects than high-dose folic acid.
• Both folic acid and multivitamins reduced some congenital cardiovascular malformations.
• Multivitamins uniquely reduced obstructive urinary tract defects, limb deficiencies, and pyloric stenosis; folic acid helped prevent rectal/anal atresia/stenosis and orofacial clefts.

Conclusions:

• Periconceptional multivitamins containing 0.4-0.8 mg folic acid are more effective than high-dose folic acid for preventing neural-tube defects.
• Multivitamin supplementation offers broader protection against various congenital abnormalities compared to folic acid alone.
• Both strategies reduce overall congenital abnormalities, but multivitamins provide more comprehensive prevention.