title: Permanently increased conductance of the murine uterine arcade after the first pregnancy.
abstract: Mechanical forces due to increased blood flow during the first pregnancy might induce a permanently higher conductance of the uterine arcade. Number of endothelial and smooth muscle cells, cross-sectional area and wall thickness of the uterine artery were measured in nulliparous mice (n = 11) and until the 93rd day after parturition in primiparous mice (n = 44). Inner diameter and wall area were calculated. Three months after the first pregnancy, uterine artery wall thickness was not altered compared to nulliparous mice. In contrast, inner diameter increased 1.6-fold, wall area 1.5-fold and the numbers of endothelial and smooth muscle cells increased 1.5 times. These changes were completely stable during the whole observation period. The increased blood flow during the first pregnancy might be a mandatory mechanical stimulus for uterine arcade maturation. This physiological maturation process could result in abortion explaining the higher prevalence of unexplained pregnancy losses in primiparous women.
authors.affiliation: Institute of Veterinary Physiology, Vetsuisse Faculty and Center for Integrative Human Physiology, University of Zürich, Zürich, Switzerland.
authors.forename: Katrin
authors.initials: K
authors.lastname: Wassel
authors.forename: Gisela
authors.initials: G
authors.lastname: Kuhn
authors.forename: Max
authors.initials: M
authors.lastname: Gassmann
authors.forename: Johannes
authors.initials: J
authors.lastname: Vogel
mesh_terms: D000818:Animals; D001158:Arteries / Q000502:physiology; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D008955:Models, Cardiovascular; D032389:Myocytes, Smooth Muscle / Q000502:physiology; D036801:Parturition; D021041:Placental Circulation / Q000502:physiology; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D013314:Stress, Mechanical; D014599:Uterus / Q000098:blood supply* / Q000166:cytology*