Obstetric denervation-gynaecological reinnervation: disruption of the inferior hypogastric plexus in childbirth as a source of gynaecological symptoms.

Difficult vaginal deliveries damage branches of the inferior hypogastric plexus as they are distributed to the pelvic viscera. The initial denervatory injury is often asymptomatic. Nerve fibre proliferation along the course of damaged nerve trunks results in chaotic reinnervation of the visceral stroma and subsequent sensory pelvic symptoms including chronic pelvic pain, painful heavy periods, painful intercourse, urinary frequency and urgency, irritable bowel symptoms and vulval pain. Each symptom may be described as pain, or discomfort, in response to light touch (allodynia). In other visceral sites allodynic syndromes are frequently associated with aberrant neural repair. Nerve fibre proliferation has now been reported in every viscus in the female pelvis though its antecedents have not been established. It is proposed that clinical presentations with one, or more, sensory pelvic symptoms occur some years after a difficult intrapartum episode; the initial denervatory injury is succeeded by nerve fibre proliferation in the affected organs. The precise pathoanatomy, mechanisms of intrapartum injury and clinical presentation remote from the intrapartum episode, may have obscured the common aetiology of many sensory pelvic syndromes.