title: Prenatal vitamin C and E supplementation in smokers is associated with reduced placental abruption and preterm birth: a secondary analysis.
abstract: OBJECTIVE
  Smoking and pre-eclampsia (PE) are associated with increases in preterm birth, placental abruption and low birthweight. We evaluated the relationship between prenatal vitamin C and E (C/E) supplementation and perinatal outcomes by maternal self-reported smoking status focusing on outcomes known to be impacted by maternal smoking.
  A secondary analysis of a multi-centre trial of vitamin C/E supplementation starting at 9-16 weeks in low-risk nulliparous women with singleton gestations.
  
  
  METHODS
  We examined the effect of vitamin C/E by smoking status at randomisation using the Breslow-Day test for interaction.
  
  
  METHODS
  The trial's primary outcomes were PE and a composite outcome of pregnancy-associated hypertension (PAH) with serious adverse outcomes. Perinatal outcomes included preterm birth and abruption.
  
  
  RESULTS
  There were no differences in baseline characteristics within subgroups (smokers versus nonsmokers) by vitamin supplementation status. The effect of prenatal vitamin C/E on the risk of PE (P = 0.66) or PAH composite outcome (P = 0.86) did not differ by smoking status. Vitamin C/E was protective for placental abruption in smokers (relative risk [RR] 0.09; 95% CI 0.00-0.87], but not in nonsmokers (RR 0.92; 95% CI 0.52-1.62) (P = 0.01), and for preterm birth in smokers (RR 0.76; 95% CI 0.58-0.99) but not in nonsmokers (RR 1.03; 95% CI 0.90-1.17) (P = 0.046).
  
  
  CONCLUSIONS
  In this cohort of women, smoking was not associated with a reduction in PE or the composite outcome of PAH. Vitamin C/E supplementation appears to be associated with a reduction in placental abruption and preterm birth among smokers.
authors.affiliation: Department of Obstetrics and Gynecology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: A
authors.initials: A
authors.lastname: Abramovici
authors.affiliation: Department of Obstetrics and Gynecology, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Gandley
authors.affiliation: Department of Obstetrics and Gynecology, The George Washington University Biostatistics Center, Washington, DC, USA.
authors.forename: R G
authors.initials: RG
authors.lastname: Clifton
authors.affiliation: Department of Obstetrics and Gynecology, Southwestern Medical Center, University of Texas, Dallas, TX, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Leveno
authors.affiliation: Department of Obstetrics and Gynecology, University of Cincinnati, Cincinnati, OH, USA.
authors.forename: L
authors.initials: L
authors.lastname: Myatt
authors.affiliation: Department of Obstetrics and Gynecology, Columbia University, New York, NY, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Wapner
authors.affiliation: Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Thorp
authors.affiliation: Department of Obstetrics and Gynecology, Case Western Reserve University-MetroHealth Medical Center, Cleveland, OH, USA.
authors.forename: B M
authors.initials: BM
authors.lastname: Mercer
authors.affiliation: Department of Obstetrics and Gynecology, Northwestern University, Chicago, IL, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Peaceman
authors.affiliation: Department of Obstetrics and Gynecology, The Ohio State University, Columbus, OH, USA.
authors.forename: P
authors.initials: P
authors.lastname: Samuels
authors.affiliation: Department of Obstetrics and Gynecology, Drexel University, Philadelphia, PA, USA.
authors.forename: A
authors.initials: A
authors.lastname: Sciscione
authors.affiliation: Department of Obstetrics and Gynecology, Wake Forest University Health Sciences, Winston-Salem, NC, USA.
authors.forename: M
authors.initials: M
authors.lastname: Harper
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX, USA.
authors.forename: G
authors.initials: G
authors.lastname: Saade
authors.affiliation: Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Sorokin
mesh_terms: D000037:Abruptio Placentae / Q000453:epidemiology*; D000293:Adolescent; D000328:Adult; D001205:Ascorbic Acid / Q000008:administration & dosage; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000453:epidemiology*; D011225:Pre-Eclampsia / Q000453:epidemiology*; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D012907:Smoking / Q000453:epidemiology*; D014810:Vitamin E / Q000008:administration & dosage; D014815:Vitamins / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D014815:Vitamins; D014810:Vitamin E; D001205:Ascorbic Acid
keywords: Placental abruption; preterm birth; smoking