OBJECTIVE To determine the effect of patient-controlled combined spinal epidural analgesia (PCEA) on maternal pulse and blood pressure, and fetal heart rate in primigravid women, when adapting different positions in labour. METHODS A prospective study. METHODS Queen Charlotte's and Chelsea hospital, London. METHODS Fifty-five primigravid women in labour at > or = 37 weeks of gestation; 40 women had supervised standing top-ups given by an anaesthetist. A further 15 women had PCEA top-ups given in each of standing, sitting and lying positions. METHODS Maternal pulse rate, blood pressure and fetal heart rate changes following epidural top-ups. RESULTS In the first 40 women there was no clinically significant fall in their blood pressure (< 5 mmHg). The subsequent 15 women who had PCEA top-ups had no fall in blood pressure in the standing and sitting positions, though the average blood pressure fell significantly when a top-up was given in the lying position. Maternal heart rate increased significantly at 12 min post top-up when the women were in the standing position (P = 0.0018). In the 15 women who had PCEA top-ups, the CTG showed improvement in decelerations when women were in the standing position but deterioration when in the lying position (P < 0.01). CONCLUSIONS Patient-controlled epidural analgesia top-ups with maternal mobility may be beneficial to the fetus possibly by reducing the hypotension normally associated with top-ups in the lying position.