Patients
We included women with singleton gestations at term (> 37 weeks) between 18 and 45 years of age admitted due to spontaneous labour onset. Exclusion criteria were 1) previous or current comorbidities (preeclampsia, gestational diabetes, recurrent urinary tract infections, or an episode of vaginal bleeding during the second half of pregnancy); 2) maternal pyrexia at admission, defined as a temperature of 38.0 °C once or 37.5 °C on two occasions two hours apart. 3) tobacco exposure in the previous 24 hours; 4) haemoglobin level <9 g/dL; 5) contraindications or refusal of neuraxial blockade; and 6) current use of medications with known influence on the cardiovascular system. Additionally, patients with failed neuraxial blockade or replacement of the epidural catheter due to inadequate pain control were not included in the final analysis. Patients were classified according to whether they were under NLA during labour.