Treatment of hypertension in pregnancy (Box 1)
The use of antihypertensive drugs in hypertensive women
without renal impairment is considered by some to be beneficial
in preventing sudden increases in blood pressure, cerebral haemorrhage
or hypertensive encephalopathy. The Control of Hypertension
in Pregnancy Study (CHIPS) is a randomised
controlled trial in which women with hypertension in pregnancy
were randomised to either ‘less tight’ control (aiming for diastolic
BP of 100 mmHg) or ‘tight’ control (aiming for diastolic BP of 85
mmHg) of their hypertension. The trial demonstrated that
women in ‘less tight’ compared with ‘tight’ control groups had
similar rates of adverse perinatal (31.4% vs. 30.7%) and
maternal outcomes (3.7% vs. 2.0%), despite higher mean diastolic
blood pressures by 4.6 mmHg. However, severe hypertension
(160/110 mmHg) developed more frequently in ‘less
tight’ (vs. ‘tight’) control (40.6% vs. 27.5%). As a result tight
control of blood pressure is advocated to prevent potential
adverse maternal outcomes.