Folic acid supplementation and the occurrence of congenital heart defects, orofacial clefts, multiple births, and miscarriage

• Published in: The American journal of clinical nutrition 2005-05, Vol.81 (5), p.1213S-1217S
• Main Authors: Bailey, L.B, Berry, R.J
• Format: Article
• Language: English
• Subjects: abortion (animals); Abortion, Spontaneous - prevention & control; Biological and medical sciences; Birth defects; cleft palate; Cleft Palate - prevention & control; congenital abnormalities; Dietary supplements; Feeding. Feeding behavior; Female; folic acid; Folic Acid - therapeutic use; Fundamental and applied biological sciences. Psychology; health promotion; Heart; Heart Defects, Congenital - prevention & control; Hematinics - therapeutic use; Humans; Infant, Newborn; maternal nutrition; Miscarriage; multiple births; Pregnancy; pregnancy outcome; Pregnancy, Multiple - drug effects; pregnant women; risk reduction; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vitamin B; vitamin supplements; Vitamins - therapeutic use
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/81.5.1213

Key research findings relative to the question of whether maternal use of folic acid before and during pregnancy reduces the chance that offspring will be born with a congenital heart defect or an orofacial cleft are reviewed in this paper. Observational studies in general support an association between maternal use of multivitamins containing folic acid and a reduction in the occurrence of congenital heart defects and orofacial clefts. Results from one randomized controlled trial (RCT) provide the strongest evidence that multivitamins prevent congenital heart defects, but this RCT did not provide evidence that multivitamins prevent orofacial clefts. In addition, most observational and interventional studies are not designed to detect an independent effect from folic acid. Early studies suggested that periconceptional multivitamin use was associated with an increased occurrence of both miscarriages and multiple births, which has resulted in a great deal of controversy about the safety of folic acid use during pregnancy. We also review reports that were designed to answer these questions with more definitive data. When more substantial evidence about the effect of periconceptional folic acid on the occurrence of congenital heart defects and orofacial clefts is reported, we will have additional support for promoting folic acid intervention programs. All women capable of becoming pregnant should continue to consume 400 microgram/d of folic acid in addition to a healthy diet as advised.