title: Seasonal variations of vitamin D concentrations in pregnant women and neonates in Slovenia.
abstract: OBJECTIVE
  While foreign research shows a high prevalence of vitamin D deficiency in pregnant women and consequently in neonates, we do not have any data on vitamin D concentration in these risk groups for Slovenia. We performed a prospective study to evaluate vitamin D concentration in pregnant women and neonates in Maribor region.
  
  
  METHODS
  We determined 25-hydroxy-vitamin D concentration from blood samples taken before delivery from 100 pregnant women who gave birth in Maribor University Clinical Centre in September and December 2013, respectively, and from the cord blood of their neonates. We collected data on nutrition and sun exposure during pregnancy. We calculated the vitamin D concentrations in pregnant women and neonates according to season of birth and use of nutrition supplements, determined the vitamin D levels in some pregnancy complications and checked the correlation of maternal and neonatal vitamin D concentrations.
  
  
  RESULTS
  The average vitamin D concentration in the September group was 54.3±25.2nmol/L, and in the December group 33.3±18.6nmol/L (p<0.001). Optimal vitamin D concentration (>80nmol/L) was reached by 12.0% of pregnant women in September and by only 2.0% in December. Women who took nutrition supplements containing vitamin D during pregnancy had significantly higher vitamin D levels than those who did not (September 68.9±27.0nmol/L vs. 46.5±20.3nmol/L, p<0.001; December 38.7±17.9nmol/L vs. 30.2±18.4nmol/L, p=0.028). Neonates had higher average levels of vitamin D than their mothers but there was a good correlation between maternal and neonatal vitamin D values.
  
  
  CONCLUSIONS
  Vitamin D deficiency is very common in pregnant women in Slovenia as well, especially in winter and in those women who do not take nutrition supplements containing vitamin D.
authors.affiliation: University Clinic for Gynaecology and Perinatology, Maribor University Medical Centre, Ljubljanska 5, 2000 Maribor, Slovenia. Electronic address: andrazdovnik@gmail.com.
authors.forename: Andraž
authors.initials: A
authors.lastname: Dovnik
authors.affiliation: University Clinic for Gynaecology and Perinatology, Maribor University Medical Centre, Ljubljanska 5, 2000 Maribor, Slovenia.
authors.forename: Faris
authors.initials: F
authors.lastname: Mujezinović
authors.affiliation: University Clinic for Gynaecology and Perinatology, Maribor University Medical Centre, Ljubljanska 5, 2000 Maribor, Slovenia.
authors.forename: Milena
authors.initials: M
authors.lastname: Treiber
authors.affiliation: Department of Internal Medicine, University of Maribor Faculty of Medicine, Taborska 8, 2000 Maribor, Slovenia.
authors.forename: Breda
authors.initials: B
authors.lastname: Pečovnik Balon
authors.affiliation: Department of Laboratory Diagnostics, University Medical Centre Maribor, Ljubljanska 5, 2000 Maribor, Slovenia.
authors.forename: Maksimiljan
authors.initials: M
authors.lastname: Gorenjak
authors.affiliation: Department of Pharmacology and Experimental Toxicology, University of Maribor Faculty of Medicine, Taborska 8, 2000 Maribor, Slovenia.
authors.forename: Uroš
authors.initials: U
authors.lastname: Maver
authors.affiliation: University Clinic for Gynaecology and Perinatology, Maribor University Medical Centre, Ljubljanska 5, 2000 Maribor, Slovenia; Department of Gynaecology and Perinatology, University of Maribor Faculty of Medicine, Taborska 8, 2000 Maribor, Slovenia.
authors.forename: Iztok
authors.initials: I
authors.lastname: Takač
mesh_terms: D000293:Adolescent; D000328:Adult; D019587:Dietary Supplements; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D007231:Infant, Newborn; D008875:Middle Aged; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood* / Q000517:prevention & control; D011446:Prospective Studies; D012621:Seasons; D017524:Slovenia; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood*; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Neonates; Nutritional Supplements; Pregnancy; Season; Vitamin D