Maternal fever (T ≥ 38 °C, 100.4 °F) during the course of labor is surprisingly uncommon given the number of potential pathogens in the genitourinary (GU) and gastrointestinal (GI) tracts and the nonsterile conditions of labor and delivery. Despite the relative rarity of maternal fever, providers should monitor maternal temperature regularly and be prepared to intervene appropriately if maternal fever develops. In general, intraamniotic infection should be presumed in patients with fever. Isolated maternal fever is defined as a maternal temperature > 38.0 and < 39.0 with no additional risk factors noted. Any measured temperature at or above 39.0 with or without additional risk factors should be considered diagnostic of chorioamnionitis (this is summarized in Table 28.1). Maternal risk factors include persistent elevated fetal heart rate, elevated maternal white blood cell count, or purulent cervical discharge.