Autonomic denervation: A new aetiological framework for clinical obstetrics and gynaecology.

The hypothesis is that many clinical conditions in obstetrics and gynaecology result from the diverse and varying consequences of injuries to pelvic autonomic nerves. These injuries result from difficult first labours, persistent physical efforts during defaecation, and, medical and surgical techniques for evacuation of the uterus. The neuro-immunohistochemical "signatures" of these injuries are variations of the Dixon-Robertson-Brosens (DRB) lesion in preeclampsia, where there is hyperplasia of the tunica intima and media of arterioles with narrowing of the lumen of the vessel. In stage IV, nulliparous "endometriosis" (and other gynaecological conditions) there are circumferential layers of abnormal nerves around a narrowed arteriole, whereas in early-onset preeclampsia (and other obstetric conditions) there are similar histological findings in uterine arterioles but there is no sign of injured nerves. During pregnancy there is elongation of blood vessels but no elongation of injured nerves leading to relative denervation of the myometrium. These lesions are detectable in most of the "great" obstetric syndromes, and, across the spectrum of gynaecological syndromes. They provide a coherent explanation of the natural history and clinical presentations of many of these syndromes. Clinical features vary with the site, nature and extent of the injury; a minor injury may enable pregnancy though it is complicated by late-onset pre-eclampsia whereas a more extensive injury may prevent pregnancy and present with chronic pelvic pain with, or without, endometriosis.