Intrauterine contraception: incidence and factors associated with uterine perforation—a population-based study

STUDY QUESTIONWhat are the incidence and factors associated with uterine perforation by modern copper intrauterine device (Cu-IUD) and the levonorgestrel-releasing intrauterine system (LNG-IUS)?SUMMARY ANSWERPerforation 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.WHAT IS KNOWN AND WHAT THIS PAPER ADDSThe 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 METHODThis 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.PARTICIPANTS AND SETTINGRecords of 108 patients with probable uterine perforation by an IUD/IUS were analysed leaving 68 patients treated for uterine perforation.RECRUITMENT/SAMPLING STRATEGYPatients 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.DATA ANALYSIS METHODPatients 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.MAIN FINDINGSThe 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.IMPLICATIONSThe 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.BIAS LIMITATIONS AND GENERALIZABILITYAs 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.STUDY FUNDING/POTENTIAL COMPETING INTERESTSHelsinki University Central Hospital research funds are acknowledged.