Perinatal morbidity in chronic hypertension

Br J Obstet Gynaecol. 1996 Feb;103(2):123-9. doi: 10.1111/j.1471-0528.1996.tb09662.x.


Objective: To investigate if chronic hypertension in the absence of superimposed pre-eclampsia is associated with increased perinatal morbidity (especially small for gestational age babies and preterm deliveries) when compared to the general obstetric population.

Design: A retrospective cohort study.

Setting: A tertiary referral obstetric hospital.

Participants: One hundred and fifty-five pregnant women with chronic hypertension who had a diastolic blood pressure of greater than 90 mmHg before 20 weeks or had pre-existing essential hypertension were studied. The study period was January 1 1991 to June 30 1993.

Main outcome measures: Perinatal related loss rate, birthweight less than the fifth centile (small for gestational age) preterm delivery, placental abruption and development of superimposed pre-eclampsia.

Results: Women with chronic hypertension without superimposed pre-eclampsia had an increased rate of small for gestational age babies (10.9%) compared with the general population (4.1%) (odds ratio 2.9 -confidence interval 1.6 to 5.0). Women with chronic hypertension without superimposed pre-eclampsia did not have a significant increase in preterm delivery or perinatal loss. Severe hypertension (diastolic blood pressure > or =110) at less than 20 weeks was associated with a trend to an increased risk of small for gestational age babies (odds ratio 3.8 -confidence interval 1.0 to 13.7-), increased rate of delivery at less than 32 weeks (odds ratio 7.4 -confidence interval 1.9 to 29.5-) and increased rate of superimposed pre-eclampsia (odds ratio 5.2 -confidence interval 1.5 to 17.2-). Women with superimposed pre-eclampsia had the greatest perinatal morbidity.

Conclusions: Women with chronic hypertension without pre-eclampsia have an increased risk of delivering a small for gestational age baby. Perinatal morbidity and pre-eclampsia is greatest in women with severe hypertension at less than 20 weeks. Preterm delivery is more common in women with superimposed pre-eclampsia.

MeSH terms

  • Adult
  • Aspirin / therapeutic use
  • Chronic Disease
  • Cohort Studies
  • Female
  • Fetal Death
  • Humans
  • Hypertension / complications*
  • Hypertension / drug therapy
  • Infant Mortality*
  • Infant, Newborn
  • Infant, Small for Gestational Age
  • Pre-Eclampsia / mortality
  • Pregnancy
  • Pregnancy Complications, Cardiovascular* / drug therapy
  • Prevalence
  • Retrospective Studies


  • Aspirin