title: Vitamin D, pre-eclampsia, and preterm birth among pregnancies at high risk for pre-eclampsia: an analysis of data from a low-dose aspirin trial.
abstract: OBJECTIVE
  To examine the relation between maternal vitamin D status and risk of pre-eclampsia and preterm birth in women at high risk for pre-eclampsia.
  
  
  METHODS
  Analysis of prospectively collected data and blood samples from a trial of prenatal low-dose aspirin.
  
  
  METHODS
  Thirteen sites across the USA.
  
  
  METHODS
  Women at high risk for pre-eclampsia.
  
  
  METHODS
  We measured 25-hydroxyvitamin D [25(OH)D] concentrations in stored maternal serum samples drawn at 12-26 weeks' gestation (n = 822). We used mixed effects models to examine the association between 25(OH)D and risk of pre-eclampsia and preterm birth, controlling for confounders including prepregnancy BMI and race.
  
  
  METHODS
  Pre-eclampsia and preterm birth.
  
  
  RESULTS
  Twelve percent of women were vitamin D deficient [25(OH)D <30 nmol/l]. Women with 25(OH)D <30 versus ≥75 nmol/l had a 2.4-fold (95% CI 1.0-5.6) higher risk of early-onset pre-eclampsia (<35 weeks' gestation) after confounder adjustment. Women with 25(OH)D <50 nmol/l had a 1.8-fold (95% CI 1.0-3.2) increased risk of preterm birth at <35 weeks compared with women who had 25(OH)D ≥75 nmol/l, which was driven by indicated preterm births at <35 weeks' gestation [25(OH)D <50 versus ≥75 nmol/l adjusted RR 2.5 (95% CI 1.1-5.8)]. There was no association between vitamin D status and pre-eclampsia or preterm birth at <37 weeks.
  
  
  CONCLUSIONS
  Maternal vitamin D status in the second trimester was inversely associated with risk of early-onset pre-eclampsia and preterm birth at <35 weeks in women at high risk for pre-eclampsia.
  
  
  CONCLUSIONS
  Vitamin D is inversely related to risk of pre-eclampsia and preterm birth at <35 weeks in high-risk pregnancies.
authors.affiliation: Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA.
authors.forename: A D
authors.initials: AD
authors.lastname: Gernand
authors.affiliation: Division of Maternal-Fetal Medicine, Magee-Women's Hospital and Department of Obstetrics, Gynecology and Reproductive Sciences, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: H N
authors.initials: HN
authors.lastname: Simhan
authors.affiliation: Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Baca
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Sciences and Department of Pediatrics, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: S
authors.initials: S
authors.lastname: Caritis
authors.affiliation: Departments of Epidemiology and Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh Graduate School of Public Health and School of Medicine, Pittsburgh, PA, USA.
authors.forename: L M
authors.initials: LM
authors.lastname: Bodnar
mesh_terms: D000328:Adult; D001241:Aspirin / Q000008:administration & dosage; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage; D006801:Humans; D011225:Pre-Eclampsia / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000453:epidemiology*; D018566:Pregnancy, High-Risk / Q000097:blood*; D047928:Premature Birth / Q000453:epidemiology* / Q000209:etiology; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D005343:Fibrinolytic Agents; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D001241:Aspirin
keywords: High-risk; pre-eclampsia; preterm birth; vitamin D