Cardiotocography (non-stress test) is the mainstay of fetal monitoring in most units. It can be
repeated regularly and easily without need of expensive equipment or highly skilled personnel. It
gives information concerning fetal wellbeing at that time but has little predictive value. If the
woman is in labour then continuous electronic fetal monitoring is appropriate.23
The main pathology affecting the fetus, apart from prematurity, is placental insufficiency leading to
intrauterine growth restriction (IUGR). IUGR occurs in around 30% of pre-eclamptic pregnancies.
Ultrasound assessment of fetal size, at the time of the initial presentation with hypertension, is a
valuable one-off measurement to assess fetal growth. Growth restriction is usually asymmetrical so
measurement of the abdominal circumference is the best method of assessment.24 Reduced liquor
volume is also associated with placental insufficiency and fetal growth restriction. Serial
estimations of liquor volume can detect fetal compromise. Randomised trials have shown that
investigation with umbilical artery Doppler assessment, using absent or reversed-end diastolic flow,
improves neonatal outcome25 and serial investigations of this and other fetal vessels can be used to
follow pregnancies under treatment and optimise delivery.24