Hypertensive disorders in pregnancy: a population-based study

Christine L Roberts, Jane B Ford, David J Henderson-Smart, Charles S Algert and Jonathan M Morris
Med J Aust 2005; 182 (7): 332-335.


Objectives: To determine population-based rates and outcomes of hypertensive disorders in pregnancy.

Design: Cross-sectional study using linked population databases.

Setting and participants: All women, and their babies, discharged from hospital following birth in New South Wales, between 1 January 2000 and 31 December 2002.

Main outcome measures: Rates of hypertensive disorders in pregnancy, maternal and infant morbidity and mortality, and level of hospital care for the birth admission.

Results: 250 173 women and their 255 931 infants were included in the study. Overall, 24 517 women (9.8%) had a hypertensive disorder in pregnancy, including 1411 (0.6%) with chronic hypertension, 10 379 (4.2%) with pre-eclampsia, 731 (0.3%) with chronic hypertension with superimposed pre-eclampsia, and 10 864 (4.3%) with gestational hypertension. Women with, and infants exposed to, hypertension were more likely to suffer death or major morbidity than those without hypertension. Infants of mothers with hypertension were more likely to be to born preterm and small for gestational age. Just over half the women with major morbidity or mortality delivered in hospitals with a high level of medical care. In contrast, most infants with major morbidity or mortality were delivered in hospitals with neonatal intensive care units.

Conclusions: Hypertension is a common complication of pregnancy, and adverse outcomes are increased among hypertensive women and their babies. Clinicians appear to be better at identifying and seeking an appropriate level of care for pregnancies where the infant is at risk of a poor outcome than when the mother is at risk. More specific antenatal indicators of poor maternal outcome would help guide the referral of hypertensive women to higher levels of care.

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  • Christine L Roberts1
  • Jane B Ford2
  • David J Henderson-Smart3
  • Charles S Algert4
  • Jonathan M Morris5

  • 1 Centre for Perinatal Health Services Research, Sydney, NSW.
  • 2 Heart and Vascular Disease Program, The George Institute, Camperdown, NSW.
  • 3 Northern Clinical School, University of Sydney, St Leonards, NSW.


Christine Roberts is supported by a National Health and Medical Research Council (NHMRC) Public Health Practitioner Fellowship. Jane Ford is supported by the Health Evaluation and Research Outcomes Network (HERON), an NHMRC Capacity Building Grant in Population Health Research. We wish to acknowledge the efforts of the hospital staff in collecting the data and the NSW Health Department staff in maintaining the HOIST data warehouse system.

Competing interests:

None identified.

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