Study Population
We recruited a retrospective cohort of patients who diagnosed with intrapartum fever (defined as temperature over 37.5 ℃) from January 1, 2018 to December 31, 2018 at Nanjing Maternity and Child Health Care Hospital. For the study group was the women with intrapartum fever, we randomly selected others, parturients who were afebrile, as the control group. All parturients selected in this study received epidural analgesia.