Maternal pyrexia associated with the use of epidural analgesia in labour.

To establish the effect of pain relief on maternal temperature during labour forty patients who went into spontaneous labour with a single fetus, had a normal temperature (less than 37.5 degrees C), and had no clinical evidence of infection were investigated prospectively. They were divided into two comparable groups--one receiving pethidine and the other epidural analgesia. Both groups had much the same temperatures at the beginning of labour and before any analgesic administration. The mean temperature in the pethidine group remained constant during labour, whereas in the epidural analgesia group it showed a significant rise after only 6 hours of labour. This rise was not related to any clinical evidence of infection. Patients receiving epidural analgesia during labour are at increased risk of developing pyrexia. This pyrexia may be the result of vascular and thermoregulatory modifications induced by epidural analgesia.