title: The prevalence of pre-eclampsia in migrant relative to native Norwegian women: a population-based study.
abstract: OBJECTIVE
  To compare the prevalence of pre-eclampsia in migrant women with Norwegian women, and to study the prevalence of pre-eclampsia by length of residence in Norway.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  The Medical Birth Registry of Norway.
  
  
  METHODS
  All Norwegian, Pakistani, Vietnamese, Somali, Sri Lankan, Filipino, Iraqi, Thai and Afghan women who gave birth after 20 weeks of gestation during the period 1986-2005 in Norway.
  
  
  METHODS
  The prevalence of pre-eclampsia was calculated by country of birth. The association of country of birth and length of residence in Norway with pre-eclampsia was estimated as the odds ratio (OR) with 95% confidence interval (CI), using Norwegian women as a reference. We made adjustments for maternal age, parity, multifetal pregnancy, year of delivery and maternal diabetes in multivariable analysis.
  
  
  METHODS
  Pre-eclampsia.
  
  
  RESULTS
  Migrant women had a lower prevalence of pre-eclampsia than Norwegian women (2.7% versus 3.7%, P < 0.001). Vietnamese (OR, 0.36; CI, 0.29-0.45), Afghan (OR, 0.52; CI, 0.30-0.90) and Thai (OR, 0.57; CI, 0.45-0.73) women had the lowest risk of pre-eclampsia relative to Norwegian women. Adjustment for the variables above or separate analyses for nulliparous women did not change the estimates notably. Using Norwegian women as the reference, the risk of pre-eclampsia increased by length of residence for migrant women: adjusted OR of 0.64 (0.59-0.70) at <5 years and 0.91 (0.84-0.99) at ≥5 years of residence.
  
  
  CONCLUSIONS
  The risk of pre-eclampsia was lower in migrants relative to Norwegian women, but increased by length of residence in Norway.
authors.affiliation: Department of Obstetrics and Gynaecology, Institute of Clinical Medicine, Akershus University Hospital, Lørenskog, Norway.
authors.forename: Z
authors.initials: Z
authors.lastname: Naimy
authors.affiliation: Department of Obstetrics and Gynaecology, Institute of Clinical Medicine, Akershus University Hospital, Lørenskog, Norway.|Department of Community Dentistry, University of Oslo, Oslo, Norway.
authors.forename: J
authors.initials: J
authors.lastname: Grytten
authors.affiliation: BI Norwegian Business School, Oslo, Norway.
authors.forename: L
authors.initials: L
authors.lastname: Monkerud
authors.affiliation: Department of Obstetrics and Gynaecology, Institute of Clinical Medicine, Akershus University Hospital, Lørenskog, Norway.|Department of Mental Health, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: A
authors.initials: A
authors.lastname: Eskild
mesh_terms: D000328:Adult; D054242:Emigrants and Immigrants; D005260:Female; D006801:Humans; D016015:Logistic Models; D015999:Multivariate Analysis; D009664:Norway / Q000453:epidemiology; D016017:Odds Ratio; D011225:Pre-Eclampsia / Q000453:epidemiology / Q000208:ethnology*; D011247:Pregnancy; D015995:Prevalence; D012042:Registries; D012306:Risk
keywords: Ethnicity; migrants; pre-eclampsia; pregnancy complications