title: Hypertensive disorders in pregnancy and fetal death at different gestational lengths: a population study of 2 121 371 pregnancies.
abstract: OBJECTIVE
  To compare the proportion of offspring that was stillborn in pregnancies with pre-eclampsia, gestational hypertension or chronic hypertension with those in normotensive pregnancies.
  
  
  METHODS
  Register-based observational study.
  
  
  METHODS
  The Medical Birth Registry of Norway.
  
  
  METHODS
  All singleton births after 20 completed weeks of gestation in Norway from 1967 to 2006 (n = 2 121 371).
  
  
  METHODS
  The proportion of stillborn offspring was estimated in normotensive pregnancies, and in pregnancies with pre-eclampsia, gestational and chronic hypertension at different gestational lengths. In addition, changes in the proportions of stillborn offspring by maternal hypertensive disorder from 1967-1986 to 1987-2006 were estimated.
  
  
  METHODS
  Fetal death.
  
  
  RESULTS
  The prevalence of hypertensive disorders in pregnancy was 4.7%. In total, 17 933 fetal deaths occurred and 9.2% of these were in hypertensive pregnancies. In normotensive pregnancies, 0.8% (16 290/2 022 400) experienced fetal death. This was true for 1.9% (1170/62 261) of the pregnancies with pre-eclampsia, 1.2% (390/32 068) with gestational hypertension and 1.8% (83/4642) with chronic hypertension. There was a 44% overall reduction in fetal death rate from 1967-1986 to 1987-2006. The largest decline was in women with pre-eclampsia (80% reduction). In women with gestational hypertension and chronic hypertension, the overall reductions in fetal death rates were 49% and 57%, respectively, comparable with the 41% decline in normotensive pregnancies.
  
  
  CONCLUSIONS
  In our nationwide study during 1967-2006, the risk of fetal death among women with hypertensive disorders in pregnancy has been greatly reduced, especially among pre-eclamptic women at term. The risk of fetal death among women with gestational or chronic hypertension has also decreased, but in a different manner.
authors.affiliation: Department of Obstetrics and Gynaecology and Medical Faculty Division, Akershus University Hospital, Lørenskog, Norway. aahs@ahus.no
authors.forename: A S
authors.initials: AS
authors.lastname: Ahmad
authors.forename: S O
authors.initials: SO
authors.lastname: Samuelsen
mesh_terms: D016022:Case-Control Studies; D002908:Chronic Disease; D005260:Female; D005313:Fetal Death / Q000453:epidemiology / Q000209:etiology*; D005865:Gestational Age; D006801:Humans; D006973:Hypertension; D046110:Hypertension, Pregnancy-Induced / Q000453:epidemiology; D016014:Linear Models; D009664:Norway / Q000453:epidemiology; D011225:Pre-Eclampsia / Q000453:epidemiology; D011247:Pregnancy; D015995:Prevalence; D012042:Registries; D012306:Risk; D012307:Risk Factors; D050497:Stillbirth / Q000453:epidemiology