The rise in maternal temperature associated with regional analgesia in labour is harmful and should be treated

Abstract

Fusi et al. in 1989 first reported the association of raised maternal temperature with the use of epidural analgesia in labour when compared to women receiving opioid analgesia.1 Since then a number of observational and randomised studies have confirmed this association.2–10 About 6–23% of women in labour with epidural analgesia will develop clinical pyrexia >38°C. The degree of rise has been estimated to be 1°C for every seven hours of exposure to epidural analgesia.1 Thus, the clinical observation of pyrexia in labour becomes more likely after five hours of exposure to epidural analgesia. The effect is also more likely to be observed in nulliparous women because they have longer labours. Although the rate of fever with epidural analgesia varies in different studies, the association has been consistent, suggesting a causal link. The variation in reported rates is probably explained by variations in the parity of the population studied (and hence in the mean duration of labour), in baseline rates of fever in women without epidural analgesia due to differences in the susceptibility of various populations to infection, and variations in the ambient temperature. The hotter the labour and delivery room, the greater the effect is likely to be. Whatever the background rate of pyrexia in a given population, it is evident from the studies that among nulliparous women, an additional 10–15% will become febrile if they are using epidural analgesia for pain relief.11