title: Immunodetente and the 'see-saw'.
abstract: The materno-fetal relationship is governed by critical levels of progesterone (P) and prostaglandin F2 alpha (PGF2 alpha). The 'see-saw' in concentration of these molecules maintain and terminate pregnancy in placental mammals. Apart from the enhancement or suppression of uterine contractility by PGF2 alpha and P respectively, the hypothesis in these pages is that the initiating event of parturition is a maternal immunologic repudiation of the feto-placental unit. This immunoregulative theory of parturition is not in contradiction to other physico-endocrinologic theories of labour; but is here presented to further explain some, heretofore, puzzling empirical data witnessed in complications of pregnancy and induced abortion, when Pgs are employed as abortifacients.
mesh_terms: D000019:Abortifacient Agents; D005260:Female; D005327:Fetal Resorption; D005333:Fetus / Q000276:immunology; D006801:Humans; D007109:Immunity; D007165:Immunosuppression Therapy; D008954:Models, Biological; D011247:Pregnancy; D011374:Progesterone / Q000502:physiology; D011460:Prostaglandins F / Q000502:physiology
chemical_list: D000019:Abortifacient Agents; D011460:Prostaglandins F; D011374:Progesterone