To explore the relationship between transcutaneous electrical acupoint stimulation wristbands on postoperative nausea, vomiting, sleep quality and serotonin levels after cesarean section

INTERVENTION: Control group:Wear a transdermal acupoint electrical stimulation wristband with the same appearance, but only wear it without providing electrical stimulation (false stimulation).;Trial Group:Wear the transcutaneous acupoint electrical stimulation wristband and provide the set effective electrical stimulation; CONDITION: Anesthesiology PRIMARY OUTCOME: Incidence of PONV within 24 hours postoperatively; SECONDARY OUTCOME: Postoperative nausea severity (NVAS score);Plasma Serotonin Concentration ;Postoperative sleep quality (using the Richards Campbell Sleep Questionnaire RCSQ);The number of compressions of the patient‐controlled analgesic pump (PCA); INCLUSION CRITERIA: 1. Single fetus, first cesarean section; 2. Age: 25‐35 years old 3. ASA physiological status classification I‐II; 4. The Apfel PONV risk score is 2 to 4 points. 5. Sign the informed consent form.