Conclusion  This study highlights a link between infection and shrinkage in the model used. Content Type Journal ArticleDOI 10.1007/s00192-010-1245-7Authors Laurent Mamy, Department of Obstetrics and Gynecology, Carémeau Hospital, Nîmes, FranceVincent Letouzey, Department of Obstetrics and Gynecology, Carémeau Hospital, Nîmes, FranceJean-Philippe Lavigne, INSERM, Espri 26, Universite Montpellier 1, UFR Medecine, Nîmes, FranceXavier Garric, Faculty of Pharmacy, IBMM, UMR CNRS 5473, University of Montpellier 1, Montpellier, FranceJean Gondry, Department of Obstetrics and Gynecology, Centre of Gynecology and Obstetrics of Amiens, Amiens, FrancePierre Mares, Department of Obstetrics and Gynecology, Carémeau Hospital, Nîmes, FranceRenaud de Tayrac, Department of Obstet...