Hypertensive disorders in pregnancy and fetal death at different gestational lengths: a population study of 2 121 371 pregnancies

BJOG. 2012 Nov;119(12):1521-8. doi: 10.1111/j.1471-0528.2012.03460.x. Epub 2012 Aug 24.

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.

Design: Register-based observational study.

Setting: The Medical Birth Registry of Norway.

Population: 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.

Main outcome measures: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Case-Control Studies
  • Chronic Disease
  • Female
  • Fetal Death / epidemiology
  • Fetal Death / etiology*
  • Gestational Age
  • Humans
  • Hypertension
  • Hypertension, Pregnancy-Induced* / epidemiology
  • Linear Models
  • Norway / epidemiology
  • Pre-Eclampsia / epidemiology
  • Pregnancy
  • Prevalence
  • Registries
  • Risk
  • Risk Factors
  • Stillbirth / epidemiology