title: Typical prenatal vitamin D supplement intake does not prevent decrease of plasma 25-hydroxyvitamin D at birth.
abstract: OBJECTIVE
  The objective of this longitudinal study was to determine what typical vitamin D predictors influence the change in vitamin D status from mid-pregnancy to birth.
  
  
  METHODS
  Plasma 25-hydroxyvitamin D [25(OH)D] was determined at mid-pregnancy (8-20 weeks gestation) and following birth (n = 193). Usual predictors of vitamin D status [body mass index (BMI), race, season] in addition to prenatal supplemental vitamin D intake and docosahexaenoic acid (DHA) status at delivery were assessed for their interaction on the change on plasma 25(OH)D concentration between the two time points.
  
  
  RESULTS
  Forty-nine percent of women had inadequate vitamin D status [categorized as deficient (<30 nmol/L) or insufficient (30-49.9 nmol/L) by IOM guidelines] at mid-pregnancy and 82% were deficient or insufficient at birth. Plasma 25(OH)D concentration dropped 61% from mid-pregnancy to birth. Season of birth (F = 7.86, P = 0.006) and mid-pregnancy plasma 25(OH)D concentration (F = 6.17, P = 0.014) were significant variables in the change of vitamin D status while BMI, race, DHA status, and typical vitamin D intake (334 IU/day) from prenatal supplements did not have an effect. Women who delivered in summer and fall had a 1.5-fold greater plasma 25(OH)D concentration than women who delivered in winter in spring (41.1 ± 23.1 and 40.7 ± 20.5 nmol/L summer and fall, respectively, versus 27.7 ± 17.9 and 29.3 ± 21.4 nmol/L in winter and spring, respectively).
  
  
  CONCLUSIONS
  Typical supplemental vitamin D intake during pregnancy did not prevent precipitous drops in maternal plasma 25(OH)D concentration. Clinicians and dietitians should be aware of the risk of inadequate vitamin D status in pregnant women in the United States relative to their initial vitamin D status and the season of birth.
authors.affiliation: a Department of Dietetics and Nutrition , University of Kansas Medical Center , Kansas City , Kansas.
authors.forename: Marlies K
authors.initials: MK
authors.lastname: Ozias
authors.forename: Elizabeth H
authors.initials: EH
authors.lastname: Kerling
authors.forename: Danielle N
authors.initials: DN
authors.lastname: Christifano
authors.forename: Susan A
authors.initials: SA
authors.lastname: Scholtz
authors.forename: John
authors.initials: J
authors.lastname: Colombo
authors.forename: Susan E
authors.initials: SE
authors.lastname: Carlson
mesh_terms: D000293:Adolescent; D000328:Adult; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood* / Q000453:epidemiology / Q000517:prevention & control; D011295:Prenatal Care; D015995:Prevalence; D012621:Seasons; D013472:Sunlight; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology* / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000097:blood* / Q000453:epidemiology / Q000517:prevention & control; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: insufficiency; pregnancy; season; supplements and functional foods; vitamin D