Maternal temperature increase

Chorioamnionitis and its association with neonatal and maternal adverse outcomes in women with and without epidural analgesia administration

OBJECTIVE

To evaluate neonatal fever and adverse maternal and neonatal outcomes in febrile laboring women and assess whether the time interval between epidural analgesia (EA) administration and chorioamnionitis is associated with these complications.

METHODS

A retrospective cohort study at a university affiliated medical center between 2003 and 2015. Included were women who underwent term vaginal delivery attempt and diagnosed with chorioamnionitis. The primary outcomes compared between febrile women with and without EA were neonatal fever and adverse neonatal and maternal outcomes. The association between time from EA to fever (<6, 6-12, >12 h) and maternal and neonatal complications was also assessed.

RESULTS

During the study period, 1,933 women with chorioamnionitis were assessed. Of them, 1,810 (93.6%) received EA prior to fever and 123 (6.4%) febrile parturients did not receive EA. Neonatal fever and other neonatal adverse outcomes were similar in the EA vs. non-EA group (2.2% vs. 0.8% and 2.7% vs. 4.9% (NS)), except for transient tachypnea of the newborn rates which were lower in the EA group (1.4% vs. 4.1%, p = 0.043). Maternal complications were similar, besides for higher rates of instrumental deliveries found in the EA group (24.0% vs. 5.7%, p < 0.001). Time between EA and fever onset was not associated with neonatal complications in logistic regression analysis.

CONCLUSION

Neonatal and maternal outcomes are similar in febrile laboring women with and without EA. The time interval between EA and onset of fever is not associated with increased rates of neonatal fever or adverse outcomes and should not affect the management of labor.

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.

Inflammation and Epidural-Related Maternal Fever: Proposed Mechanisms

Intrapartum fever is associated with excessive maternal interventions as well as higher neonatal morbidity. Epidural-related maternal fever (ERMF) contributes to the development of intrapartum fever. The mechanism(s) for ERMF has remained elusive. Here, we consider how inflammatory mechanisms may be modulated by local anesthetic agents and their relevance to ERMF. We also critically reappraise the clinical data with regard to emerging concepts that explain how anesthetic drug-induced metabolic dysfunction, with or without activation of the inflammasome, might trigger the release of nonpathogenic, inflammatory molecules (danger-associated molecular patterns) likely to underlie ERMF.