Transcutaneous auricular vagus nerve stimulation after cesarean delivery: current evidence and trial design...

Post-cesarean recovery includes uterine contraction pain, incisional pain, nausea, sleep loss, breastfeeding concerns, and early mood symptoms. Transcutaneous auricular vagus nerve stimulation (taVNS) is a non-invasive neuromodulation method that has recently been tested after cesarean delivery. This review summarizes the current evidence and asks how future studies should be designed. A structured search of PubMed, Embase, Web of Science Core Collection, Cochrane CENTRAL, ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, Chinese Clinical Trial Registry, China National Knowledge Infrastructure, and Wanfang was used to identify direct obstetric studies, selected perioperative studies from non-obstetric surgery, and mechanistic papers relevant to post-cesarean recovery. In total, 18 studies were retained. Only one adequately powered randomized trial directly tested taVNS after cesarean delivery. In that trial, 156 women undergoing elective cesarean delivery received active or sham taVNS once daily on the day of surgery and postoperative days 1 and 2. Active stimulation was associated with a lower incidence of moderate-to-severe uterine contraction pain on postoperative day 3. Early incisional pain, sleep, anxiety, and EPDS scores also favored active stimulation, but one-month anxiety and EPDS scores did not differ. Evidence for postoperative nausea and vomiting, ileus, lactation, and postpartum depression prevention remains indirect or trial-stage only. Current evidence supports further multicenter obstetric trials of taVNS, mainly for uterine contraction pain. It does not support routine clinical use. Future studies should use clear sham procedures, formal blinding assessment, objective biomarkers, lactation outcomes, and follow-up to at least 6 weeks postpartum.