Umbilical artery flow velocity waveforms were obtained using continuous-wave Doppler ultrasound to examine the effect of epidural analgesia on peak systolic/least diastolic ratio (A/B ratio) in 38 women in uncomplicated labour, and 12 women with pregnancy-induced hypertension (PIH). In the uncomplicated group there was no significant change in A/B ratio after epidural analgesia, but in the PIH group there was significant correlation between the fall in mean blood pressure and the fall in A/B ratio at 30 min after induction of epidural analgesia (r = 0.85, p less than 0.001). This suggests that epidural analgesia in PIH is associated with a reduction in placental resistance and may be beneficial to the fetus.