title: Vitamin D testing in pregnancy: Does one size fit all?
abstract: BACKGROUND
  Vitamin D deficiency is common. What the optimum level of vitamin D in pregnancy and whether vitamin D supplementation in pregnancy confers improved health benefits remain controversial.
  
  
  OBJECTIVE
  To assess vitamin D status in pregnant women in a maternity service that recommends routine antenatal screening and advises supplementation where necessary, and to assess relationships between early pregnancy vitamin D levels and changes in vitamin D across pregnancy with pregnancy outcomes.
  
  
  METHODS
  Vitamin D serum concentrations were measured in early and late pregnancy. The relationships between initial vitamin D status, maternal factors and pregnancy outcomes were estimated. Change in vitamin D over pregnancy was quantified. The relationship between change in vitamin D over pregnancy and pregnancy outcomes was also estimated.
  
  
  RESULTS
  Of 1550 women, 849 (55%) were vitamin D deficient (<50 nmol/L), 571 (37%) were insufficient (50-74 nmol/L), and 130 (8%) were replete (≥75 nmol/L) in early pregnancy. Factors associated with deficiency were increased body mass index, pregnancy in either winter or spring months, and maternal country of birth (South-East, South and East Asia, and Africa). Vitamin D deficiency or insufficiency in early pregnancy was significantly associated with developing gestation diabetes mellitus. Levels of vitamin D significantly increased over pregnancy among nonreplete women. Increasing vitamin D over pregnancy was not related to pregnancy outcomes.
  
  
  CONCLUSIONS
  Vitamin D 'deficiency' is common but may not be associated with most adverse pregnancy outcomes. Routine vitamin D testing of all pregnant women does not appear warranted.
authors.affiliation: The Ritchie Centre, MIMR-PHI Institute of Medical Research, Clayton, Vic., Australia; Department of Obstetrics and Gynaecology, School of Clinical Sciences, Monash University, Clayton, Vic., Australia.
authors.forename: Miranda
authors.initials: M
authors.lastname: Davies-Tuck
authors.forename: Cheryl
authors.initials: C
authors.lastname: Yim
authors.forename: Michelle
authors.initials: M
authors.lastname: Knight
authors.forename: Ryan
authors.initials: R
authors.lastname: Hodges
authors.forename: James C G
authors.initials: JC
authors.lastname: Doery
authors.forename: Euan
authors.initials: E
authors.lastname: Wallace
mesh_terms: D000328:Adult; D000349:Africa / Q000208:ethnology; D001210:Asia, Southeastern / Q000208:ethnology; D001315:Australia / Q000453:epidemiology; D015992:Body Mass Index; D019587:Dietary Supplements; D005202:Asia, Eastern / Q000208:ethnology; D005260:Female; D006801:Humans; D011247:Pregnancy; D011248:Pregnancy Complications / Q000175:diagnosis* / Q000188:drug therapy / Q000208:ethnology; D011256:Pregnancy Outcome; D011261:Pregnancy Trimester, First / Q000097:blood; D011263:Pregnancy Trimester, Third / Q000097:blood; D011295:Prenatal Care / Q000379:methods*; D012621:Seasons; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000175:diagnosis* / Q000188:drug therapy / Q000208:ethnology; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: pregnancy; pregnancy outcomes; vitamin D