Epidural Fever: Hiding in the Shadows.

Recent research has focused on inflammation and oxidative stress that is seen in women developing intrapartum fever. The interleukin-6 (IL-6) levels have been found to be elevated in women who receive epidural analgesia and become febrile. This suggests that the epidural itself induces an inflammatory response and it is not a physiologic process of labour. Similar findings with additional proinflammatory mediators and reactive oxygen species seem to support this theory. Epidural analgesia also affects the body's thermoregulatory mechanisms. It causes an increase in shivering and appears to be associated with a decrease in heat dissipation via sweating and hyperventilation, most likely because of blockade of the sympathetic stimulation. Considering these factors, it is probable that epidurals do contribute to the development of the associated fever. There remains the possibility that subclinical chorioamnionitis might be the underlying cause of a subset of maternal intrapartum fevers. In summary, histologic chorioamnionitis and epidural analgesia appear to be the independent contributors to intrapartum fever.