title: Is first trimester vitamin D status in nulliparous women associated with pregnancy related hypertensive disorders?
abstract: OBJECTIVE
  this study aimed to explore if maternal vitamin D status in early pregnancy was associated with pre-eclampsia and pregnancy-induced hypertension. Relationships between vitamin D status and blood pressure at the start of pregnancy as well as the occurrence of a mid-pregnancy drop in blood pressure were also explored. This secondary analysis was completed to investigate a possible mechanism for the association between vitamin D status and pregnancy related hypertensive disorders.
  
  
  METHODS
  data were obtained from the Amsterdam Born Children and their Development study, a prospective community-based cohort study based in Amsterdam, The Netherlands.
  
  
  METHODS
  a total of 2074 nulliparous women without pre-existing hypertension and with a known vitamin D status before 17 weeks gestation were included in the study. Vitamin D status was categorized into four groups: "normal" (≥50nmol/L), "insufficient" (30-49.9nmol/L) "deficient" (20-29.9nmol/L) or "severely deficient" (<20nmol/L).
  
  
  METHODS
  logistic regression analysis was used to investigate if vitamin D status was related to the odds of experiencing pre-eclampsia or pregnancy-induced hypertension. Models were corrected for maternal age, ethnicity, pre-pregnancy BMI, smoking and socioeconomic status. χ(2) and ANOVA tests were used to investigate relationships between vitamin D status and the blood pressure parameters.
  
  
  RESULTS
  when compared to women with a normal vitamin D status, women who were severely deficient had an increased risk for pre-eclampsia (OR 2.08; 95% CI, 1.05-4.13), but the association was rendered non-significant after correction (OR 1.88; 95% CI 0.79-4.48). There were no associations between vitamin D status and pregnancy-induced hypertension, starting blood pressure or the occurrence of a mid-pregnancy drop in blood pressure.
  
  
  CONCLUSIONS
  no strong evidence was found for an association between first trimester vitamin D status and pregnancy related hypertensive disorders in nulliparous women.
  
  
  CONCLUSIONS
  at this time, vitamin D supplementation is not warranted for the specific purpose of preventing pregnancy related hypertensive disorders.
authors.affiliation: Department of Public Health, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands; Midwifery Academy Amsterdam, Louwesweg 6, 1066 EC, Amsterdam, The Netherlands. Electronic address: brittevanweert@hotmail.com.
authors.forename: Britte
authors.initials: B
authors.lastname: van Weert
authors.affiliation: Department of Public Health, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands; Midwifery Academy Amsterdam, Louwesweg 6, 1066 EC, Amsterdam, The Netherlands. Electronic address: denicevdberg89@gmail.com.
authors.forename: Denice
authors.initials: D
authors.lastname: van den Berg
authors.affiliation: Department of Public Health, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. Electronic address: e.j.hrudey@amc.uva.nl.
authors.forename: E Jessica
authors.initials: EJ
authors.lastname: Hrudey
authors.affiliation: Department of Public Health, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. Electronic address: a.oostvogels@amc.uva.nl.
authors.forename: Adriëtte J J M
authors.initials: AJJM
authors.lastname: Oostvogels
authors.affiliation: Department of Obstetrics and Gynaecology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. Electronic address: edemiranda@amc.uva.nl.
authors.forename: Esteriek
authors.initials: E
authors.lastname: de Miranda
authors.affiliation: Department of Public Health, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. Electronic address: t.vrijkotte@amc.uva.nl.
authors.forename: Tanja G M
authors.initials: TGM
authors.lastname: Vrijkotte
mesh_terms: D000328:Adult; D001794:Blood Pressure; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D009426:Netherlands; D010298:Parity; D011225:Pre-Eclampsia / Q000097:blood*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011446:Prospective Studies; D014807:Vitamin D / Q000097:blood*
chemical_list: D014807:Vitamin D
keywords: 25-Hydroxyvitamin D; Blood pressure; Mid-pregnancy drop; Pre-eclampsia; Pregnancy-induced hypertension