Perinatal morbidity in chronic hypertension.
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.


METHODS
A retrospective cohort study.


METHODS
A tertiary referral obstetric hospital.


METHODS
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.


METHODS
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.
McCowan
L M
LM
Department of Obstetrics and Gynaecology, National Women's Hospital, Auckland, New Zealand.
Buist
R G
RG
North
R A
RA
Gamble
G
G
D000328:Adult; D001241:Aspirin / Q000627:therapeutic use; D002908:Chronic Disease; D015331:Cohort Studies; D005260:Female; D005313:Fetal Death; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000188:drug therapy; D007226:Infant Mortality; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D011225:Pre-Eclampsia / Q000401:mortality; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000188:drug therapy; D015995:Prevalence; D012189:Retrospective Studies
D001241:Aspirin