title: [I.U.D. degradation in utero as a function of time: the phenomena of calcification. Radiocrystallographic and scanning electron microscopy study].
abstract: OBJECTIVE
  A study was undertaken in order to determine the frequency of the process of calcareous deposition, to clarify the nature of the deposits, their arrangement along the IUD and their possible influence on the appearance of metrorrhagias.
  
  
  METHODS
  A total of 408 coopper IUD's belonging to four standard models were observed by means of optical microscopy at low magnifications. The most typical samples were studied under the scanning electron microscope and deposits analyzed by crystallography. The data were analysed statistically.
  
  
  RESULTS
  It was possible to determine both the frequency and the importance of the process of calcification according to the model of IUD and to the bearing time, to demonstrate a preferential location of concretions and to suspect a sensibility to the phenomenon variable according to the model. It was also possible to clarify the stages of the process of calcification, to describe its most characteristic aspects and to identify the essential component of calcareous deposits.
  
  
  CONCLUSIONS
  Calcification concerns roughly over 50% of IUD's in utero. It occurs preferentially on the fundic portion of an IUD. Obviously, the minimal time required for the phenomenon to start as well as to increase its intensity are submitted to strong individual variations. Concretions are composed of vaterite, a distinct variety of carbonate of calcium. They do not seem to be the primary cause of possible metrorrhagias.
authors.affiliation: Laboratoire de Physiopathologie de l'Implantation et du Développement, Université P. et M. Curie, 12, rue Cuvier, 75230 Paris, France. chretien.ffc@wanadoo.fr
authors.forename: F C
authors.initials: FC
authors.lastname: Chrétien
authors.forename: J
authors.initials: J
authors.lastname: Berthou
authors.forename: P A
authors.initials: PA
authors.lastname: Driguez
mesh_terms: D002118:Calcium / Q000032:analysis*; D003461:Crystallography; D004868:Equipment Failure; D005260:Female; D006801:Humans; D007435:Intrauterine Devices, Copper; D008796:Metrorrhagia / Q000209:etiology; D008855:Microscopy, Electron, Scanning; D013997:Time Factors
chemical_list: D002118:Calcium