Extent of Vagus Innervation to the Pelvic Organs: A Scoping Review.

Abstract

Context: The vagus nerve (VN) has diverse impacts on the gastrointestinal tract, but there is conflicting and limited information on any pelvic organ innervation. Spinal cord neurological disease affects pelvic organ function, and the possibility of extraspinal innervation has implications for function and potential therapy development.

Objective: We aimed to explore current literature evidence on VN in relation to the pelvic viscera, to map the distal VN, anatomically and functionally.

Evidence acquisition: The Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for scoping reviews checklist was used. MEDLINE, EMBASE, and Scopus were systematically searched up to October 28, 2025, extracting into Covidence. Two reviewers independently screened titles, abstracts, and full texts, excluding papers not available in English, nonprimary data papers, and papers focused on unrelated systems. Data were extracted using a customised Covidence form to capture study design, methodology, and functional outcomes. Reviewer disagreements were resolved by consensus.

Evidence synthesis: Overall, 51 experimental studies were included (six human studies, 45 using animal models). Animal models suggest a direct uterine-vagal connection, with sparse anatomical evidence of the VN projecting to the distal colon, bladder, and very little evidence for testicular innervation. Human studies support the existence of vagal innervation of the female genital tract.

Conclusions: The findings challenge the traditional view of exclusive spinal innervation of pelvic organs and underscore the need for specific and focused vagal-pelvic research. Future studies should be aimed at in situ anatomical mapping in animal models, along with functional assessment in larger human cohorts to determine the extent and functionality of vagal innervation in humans.