title: A randomized trial of vitamin D supplementation in 2 community health center networks in South Carolina.
abstract: OBJECTIVE
  We sought to determine whether 4000 IU/d (vs 2000 IU/d) of vitamin D during pregnancy is safe and improves maternal/neonatal 25-hydroxyvitamin D [25(OH)D] in a dose-dependent manner.
  
  
  METHODS
  A total of 257 pregnant women 12-16 weeks' gestation were enrolled. Randomization to 2000 vs 4000 IU/d followed 1-month run-in at 2000 IU/d. Participants were monitored for hypercalciuria, hypercalcemia, and 25(OH)D status.
  
  
  RESULTS
  Maternal 25(OH)D (n = 161) increased from 22.7 ng/mL (SD 9.7) at baseline to 36.2 ng/mL (SD 15) and 37.9 ng/mL (SD 13.5) in the 2000 and 4000 IU groups, respectively. While maternal 25(OH)D change from baseline did not differ between groups, 25(OH)D monthly increase differed between groups (P < .01). No supplementation-related adverse events occurred. Mean cord blood 25(OH)D was 22.1 ± 10.3 ng/mL in 2000 IU and 27.0 ± 13.3 ng/mL in 4000 IU groups (P = .024). After controlling for race and study site, preterm birth and labor were inversely associated with predelivery and mean 25(OH)D, but not baseline 25(OH)D.
  
  
  CONCLUSIONS
  Maternal supplementation with vitamin D 2000 and 4000 IU/d during pregnancy improved maternal/neonatal vitamin D status. Evidence of risk reduction in infection, preterm labor, and preterm birth was suggestive, requiring additional studies powered for these endpoints.
authors.affiliation: Division of Neonatology, Department of Pediatrics, Medical University of South Carolina, Charleston, SC 29425, USA. wagnercl@musc.edu
authors.forename: Carol L
authors.initials: CL
authors.lastname: Wagner
authors.forename: Rebecca
authors.initials: R
authors.lastname: McNeil
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Hamilton
authors.forename: Joyce
authors.initials: J
authors.lastname: Winkler
authors.forename: Carolina
authors.initials: C
authors.lastname: Rodriguez Cook
authors.forename: Gloria
authors.initials: G
authors.lastname: Warner
authors.forename: Betty
authors.initials: B
authors.lastname: Bivens
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Davis
authors.forename: Pamela G
authors.initials: PG
authors.lastname: Smith
authors.forename: Martha
authors.initials: M
authors.lastname: Murphy
authors.forename: Judy R
authors.initials: JR
authors.lastname: Shary
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Hollis
mesh_terms: D000328:Adult; D002118:Calcium / Q000097:blood / Q000652:urine; D003151:Community Health Centers; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D006801:Humans; D008429:Maternal Welfare; D011247:Pregnancy; D011256:Pregnancy Outcome; D013022:South Carolina; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000008:administration & dosage* / Q000009:adverse effects / Q000031:analogs & derivatives / Q000097:blood; D014815:Vitamins / Q000008:administration & dosage* / Q000009:adverse effects; D055815:Young Adult
chemical_list: D014815:Vitamins; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium