Objective:To evaluate the effectiveness of esketamine during perioperative anesthesia for acute and chronic pain after cesarean section.Methods:One hundred and fifty patients scheduled for elective cesarean section under spinal anesthesia were randomly assigned into 2 equal groups ( n=75) using a random number table: esketamine group (group E) and control group (group C). Subarachnoid block was administered with 9-11 mg of hyperbaric bupivacaine with 0.33% glucose concentration. After the delivery of the fetus, 0.15 mg/kg (1 mg/ml) esketamine was pumped intravenously for 30 min in the group E, while the same dosage of normal saline was administered in the group C. Furthermore, patients received an intravenous patient controlled intravenous analgesia (PCIA) pump after surgery (100 μg sufentanil + 1.25 mg/kg esketamine + 8 mg ondansetron for the group E, 100 μg sufentanil + 8 mg ondansetron for the group C). Heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were recorded in the initial time of esketamine administration, and 5, 15 min, and 30 min after administration. The pain Numerical Rating Scale (NRS) score at rest and during coughing were recorded at 2, 6, 12, 24 h and 48 h after surgery. The first analgesic time and cumulative sufentanil consumption were recorded at 0-12 h, 12-24 h, 24-48 h, 0-24 h and 0-48 h after surgery. Moreover, we recorded the incidence of chronic pain at 3 and 6 months after surgery. Results:There were no significant differences in HR, SBP and DBP between the two groups immediately after administration of esketamine and 5, 15 min and 30 min after administration (all P>0.05). At rest or during coughing, the pain NRS score were significantly lower at 2, 6 h, and 12 h postoperatively in group E compared to group C (all P<0.05). The time to first analgesia in group E was significantly longer than the group C [(176.8±18.3)min vs (148.5±16.9)min, P<0.05]. The cumulative sufentanil consumption was significantly lower in group E during 0-12 h, 12-24 h, 0-24 h and 0-48 h postoperatively than in group C (all P<0.05), but there was no statistical significance between the two groups at 24-48 h ( P>0.05). There were no significant difference between the two groups in the incidence of chronic pain at 3 months and 6 months after surgery ( all P>0.05). The incidence of chronic pain in group E was lower than that in group C at 3 months [13.4%(9/67) vs 18.8%(13/69), P=0.392] and 6 months [10.7%(6/56) vs 16.1%(10/62), P=0.391], but the difference was not statistically significant. Conclusions:Perioperative administration of esketamine provided superior short-term analgesia after cesarean section and did not increase the psychotomimetic adverse event rate. However, the development of chronic pain was not restrained.