title: Intrauterine contraception: incidence and factors associated with uterine perforation--a population-based study.
abstract: OBJECTIVE
  What are the incidence and factors associated with uterine perforation by modern copper intrauterine device (Cu-IUD) and the levonorgestrel-releasing intrauterine system (LNG-IUS)?
  
  
  CONCLUSIONS
  Perforation incidence was similar to that reported in prior studies and did not vary between Cu-IUD and LNG-IUS groups. Lactation, amenorrhoea and a post-partum period of <6 months were common.
  
  
  BACKGROUND
  The study supports findings in prior studies. The incidence rate was low and factors associated with uterine perforation were similar to those in earlier reports. DESIGN AND DATA COLLECTION METHOD: This retrospective population-based registry study included 68 patients surgically treated for uterine perforation by an intrauterine device (IUD)/intrauterine system (IUS) at clinics in the Helsinki and Uusimaa hospital district.
  
  
  METHODS
  Records of 108 patients with probable uterine perforation by an IUD/IUS were analysed, leaving 68 patients treated for uterine perforation. RECRUITMENT/SAMPLING STRATEGY: Patients with diagnostic and surgical treatment codes indicating uterine perforation by an IUD/IUS between 1996 and 2009 were retrospectively selected from the Finnish National Hospital Register.
  
  
  METHODS
  Patients with Cu-IUDs (n = 17) and the LNG-IUS (n = 51) were analysed as one group and also compared using Mann-Whitney and chi-square tests. IUD/IUS sales numbers were used to calculate incidences.
  
  
  RESULTS
  The overall incidence of perforation was 0.4/1000 sold devices, varying annually from 0 to 1.2/1000. The proportion of both sold and perforating LNG-IUSs increased during the study period, but perforation incidence was not affected. Demographic characteristics in the Cu-IUD and LNG-IUS groups were similar. More than half of the devices (55%) were inserted at <6 months post-partum. Breastfeeding at the time of insertion was common, comprising 32% of all patients. Moreover, of the breastfeeding women, 90% had delivered within 6 month prior to insertion.
  
  
  CONCLUSIONS
  The population-based study setting represents a good overview of patients experiencing uterine perforation with an IUD/IUS. As previously reported, the post-partum period, lactation and amenorrhoea may increase the risk of perforation.
  As the study setting revealed only symptomatic patients or those attending regular follow-up, the true incidence might be somewhat higher. As there is no specific diagnostic code for uterine perforation or treatment, it is unlikely that all cases of uterine perforation can be identified in a retrospective study.
authors: Department of Obstetrics and Gynaecology,  University of Helsinki and Helsinki University Central Hospital, PO Box 610, SF-00029 HUS, Helsinki,  Finland.
authors: Janina
authors: J
authors: Kaislasuo
authors: Satu
authors: S
authors: Suhonen
authors: Mika
authors: M
authors: Gissler
authors: Pekka
authors: P
authors: Lähteenmäki
authors: Oskari
authors: O
authors: Heikinheimo
mesh_terms: D000328:Adult; D001942:Breast Feeding; D005260:Female; D006801:Humans; D007435:Intrauterine Devices, Copper / Q000009:adverse effects*; D007436:Intrauterine Devices, Medicated / Q000009:adverse effects*; D016912:Levonorgestrel / Q000008:administration & dosage; D008875:Middle Aged; D049590:Postpartum Period; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014595:Uterine Perforation / Q000209:etiology*
chemical_list: D016912:Levonorgestrel