title: Is midtrimester vitamin D status associated with spontaneous preterm birth and preeclampsia?
abstract: OBJECTIVE
  The objective of this study is to evaluate whether midtrimester maternal vitamin D is associated with preeclampsia < 37 weeks or spontaneous preterm birth (SPTB) < 35 weeks.
  
  
  METHODS
  Nested case-control comprising two case subsets: (1) 100 women with preeclampsia < 37 weeks and (2) 100 women with SPB < 35 weeks. Controls consisted of 200 women delivered between 39 and 40 weeks. Stored maternal serum obtained between 15 and 21 weeks was tested for total 25-hydroxy vitamin D (25-OH D) levels using liquid chromatography-tandem mass spectrometry. Mean 25-OH D levels and prevalence of vitamin D insufficiency (25-OH D < 30 ng/mL) and deficiency (25-OH D < 15 ng/mL) were compared.
  
  
  RESULTS
  In this study, 89 preeclampsia, 90 SPTB cases, and 177 controls had valid measurements. Mean midtrimester vitamin D was not significantly different between women with preeclampsia (27.4 ng/mL ± 14.4) and controls (28.6 ± 12.6) (p = 0.46), or SPTB (28.8 ± 13.2) and controls (p = 0.92). After adjusting for potential cofounders, neither vitamin D insufficiency (adjusted odds ratio [OR], 1.1; 95% confidence interval [CI], 0.6-2.0) nor deficiency (adjusted OR, 1.4; 95% CI, 0.7-3.0) was significantly associated with preeclampsia. Likewise, SPTB was not significantly associated with either vitamin D insufficiency or deficiency (adjusted OR, 0.8; 95% CI, 0.4-1.4, adjusted OR, 1.3 or 95% CI, 0.6-3.0, respectively).
  
  
  CONCLUSIONS
  Midtrimester maternal vitamin D was not significantly associated with preeclampsia < 37 weeks or SPTB < 35 weeks.
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Center for Women's Reproductive Health, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: Luisa A
authors.initials: LA
authors.lastname: Wetta
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Center for Women's Reproductive Health, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Biggio
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Center for Women's Reproductive Health, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Cliver
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Center for Women's Reproductive Health, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: Adi
authors.initials: A
authors.lastname: Abramovici
authors.affiliation: Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: Stephen
authors.initials: S
authors.lastname: Barnes
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Center for Women's Reproductive Health, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: Alan T N
authors.initials: AT
authors.lastname: Tita
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D011225:Pre-Eclampsia / Q000097:blood* / Q000453:epidemiology; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000097:blood*; D047928:Premature Birth / Q000097:blood* / Q000453:epidemiology; D012189:Retrospective Studies; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000453:epidemiology; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
references.citation: Am J Clin Nutr. 2004 May;79(5):717-26
references.pmid: 15113709
references.citation: Epidemiology. 2009 Sep;20(5):720-6
references.pmid: 19451820
references.citation: Obstet Gynecol. 2011 Jul;118(1):197-198
references.pmid: 21691184
references.citation: Lancet. 1982 Jan 9;1(8263):74-6
references.pmid: 6119494
references.citation: Obstet Gynecol Surv. 2010 Apr;65(4):273-84
references.pmid: 20403218
references.citation: N Engl J Med. 2007 Jul 19;357(3):266-81
references.pmid: 17634462
references.citation: BJOG. 2010 Dec;117(13):1593-8
references.pmid: 21040394
references.citation: Hypertension. 2010 Oct;56(4):758-63
references.pmid: 20733087
references.citation: J Clin Endocrinol Metab. 2007 Sep;92(9):3517-22
references.pmid: 17535985
references.citation: J Nutr. 2009 Jun;139(6):1157-61
references.pmid: 19357214
references.citation: Am J Obstet Gynecol. 2011 Sep;205(3):208.e1-7
references.pmid: 21640968
references.citation: Pediatrics. 2011 Jan;127(1):e180-7
references.pmid: 21187313
references.citation: PLoS One. 2010 Jul 13;5(7):e11555
references.pmid: 20644628
references.citation: Am J Clin Nutr. 2007 Mar;85(3):788-95
references.pmid: 17344501
references.citation: Am J Obstet Gynecol. 2010 May;202(5):429.e1-9
references.pmid: 19846050
references.citation: Am J Obstet Gynecol. 2010 Oct;203(4):366.e1-6
references.pmid: 20692641
references.citation: Am J Perinatol. 2011 Oct;28(9):667-72
references.pmid: 21500145
references.citation: Lancet. 2001 Nov 3;358(9292):1500-3
references.pmid: 11705562