title: Vitamin C supplementation in pregnancy--does it decrease rates of preterm birth? A systematic review.
abstract: OBJECTIVE
  To assess the evidence available on the use of vitamin C supplementation greater than recommended dietary intake to reduce preterm birth rates.
  
  
  METHODS
  Systematic review of randomized controlled trials using vitamin C alone or with one other supplement other than iron. Trials must report preterm birth rates but can have other primary outcomes. Preterm birth is defined as birth at less than 37 weeks' gestational age for this review. Review focused on studies with populations representative of Organization for Economic Co-operation and Development countries.
  
  
  RESULTS
  Inadequate level of evidence on the use of vitamin C alone to prevent preterm birth rates in low-risk populations based on one study. Three studies provided convincing evidence of no benefit in low-risk groups of use of vitamins C and E combined. Three studies provided adequate evidence of no benefit in high-risk groups of use of vitamins C and E combined.
  
  
  CONCLUSIONS
  The available evidence supports no benefit gained from using vitamin C to prevent preterm birth. Evidence does not support limiting use of vitamin C supplementation for other indications.
authors.affiliation: Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, North Carolina.
authors.forename: Paul
authors.initials: P
authors.lastname: Swaney
authors.affiliation: Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, North Carolina.
authors.forename: John
authors.initials: J
authors.lastname: Thorp
authors.affiliation: Department of Radiation Oncology, University of North Carolina, Chapel Hill, North Carolina.
authors.forename: Ian
authors.initials: I
authors.lastname: Allen
mesh_terms: D000975:Antioxidants / Q000627:therapeutic use*; D001205:Ascorbic Acid / Q000627:therapeutic use*; D019587:Dietary Supplements; D004359:Drug Therapy, Combination; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000517:prevention & control; D006801:Humans; D011247:Pregnancy; D047928:Premature Birth / Q000517:prevention & control*; D016032:Randomized Controlled Trials as Topic; D014810:Vitamin E / Q000627:therapeutic use
chemical_list: D000975:Antioxidants; D014810:Vitamin E; D001205:Ascorbic Acid