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Comparing the effectiveness of copper intrauterine devices available in Canada. Is FlexiT non-inferior… Norman, Wendy V; Chiles, Jessica L; Turner, Caroline A; Brant, Rollin; Aslan, Andra; Kaczorowski, Janusz Aug 24, 2012

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Comparing the effectiveness of copper intrauterinedevices available in Canada. Is FlexiT non-inferiorto NovaT when inserted immediately afterfirst-trimester abortion? Study protocol for arandomized controlled trialNorman et al.Norman et al. Trials 2012, 13:147http://www.trialsjournal.com/content/13/1/147STUDY PROTOCOL Open AccessComparing the effectiveness of copper intrauterinedevices available in Canada. Is FlexiT non-inferiorto NovaT when inserted immediately afterfirst-trimester abortion? Study protocol for arandomized controlled trialWendy V Norman1,2,3*, Jessica L Chiles1,2, Caroline A Turner1,2, Rollin Brant1,4, Andra Aslan1,2and Janusz Kaczorowski1,5AbstractBackground: We describe the rationale and protocol for a randomized noninferiority controlled trial (RCT) todetermine if the Flexi-T380(+) copper intrauterine contraceptive device (IUD) is comparable in terms of effectivenessand expulsion rates to the most common Canadian IUD currently in use, NovaT-200, when placed immediatelyafter a first-trimester abortion.Methods/Design: Consenting women choosing to use an IUD after an abortion for a pregnancy of less than 12 weeksof gestation will be randomized to device-type groups to receive immediate post-abortion placement of either aFlexi-T380(+) IUD, a device for which no current evidence on expulsion or effectiveness rates is available, or theNova-T200 IUD, the only other brand of copper IUD available in Canada at the time of study initiation. The primaryoutcome measure is IUD expulsion rate at 1 year. Secondary outcomes include: pregnancy rate, method continuationrate, complication rates (infection, perforation), and satisfaction with contraceptive method. A non-intervention group ofconsenting women choosing a range of other post-abortion contraception methods, including no contraception, will beincluded for comparison of secondary outcomes. Web-based contraception satisfaction questionnaires, clinical records,and government-linked health administrative databases will be used to assess primary and secondary outcomes.Discussion: The RCT design, combined with access to clinical records at all provincial abortion clinics, and toinformation in provincial single-payer linked administrative health databases, birth registry, and hospital records, offers aunique opportunity to determine if a novel IUD has a comparable expulsion rate to that of the current standard IUD inCanada, in addition to the first opportunity to determine pregnancy rate and method satisfaction at 1 year post-abortionfor women choosing a range of post-abortion contraceptive options. We highlight considerations of design,implementation, and evaluation of the first trial to provide rigorous evidence for the effectiveness of current CanadianIUDs when inserted after first-trimester abortion.Trial registration: ClinicalTrials.gov Identifier NCT01174225Keywords: Contraception, Intrauterine device, Intrauterine device expulsion, Contraception effectiveness,Abortion-induced, Therapeutic abortion, Non-inferiority trial, Randomized controlled trial, Canada* Correspondence: wendy.norman@ubc.ca1Contraception Access Research Team, Women’s Health Research Institute,Vancouver, British Columbia V6H 1G3, Canada2Department of Family Practice, University of British Columbia, Vancouver,British Columbia V6T 1Z3, CanadaFull list of author information is available at the end of the articleTRIALS© 2012 Norman et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the CreativeCommons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, andreproduction in any medium, provided the original work is properly cited.Norman et al. Trials 2012, 13:147http://www.trialsjournal.com/content/13/1/147BackgroundThis randomized non-inferiority controlled trial (RCT)will examine the effectiveness of post-abortion contra-ception by determining whether a new type of copperintrauterine device (IUD) in Canada has a comparableeffectiveness and safety profile to the most commonlyused Canadian IUD. Clinical experience suggests thatexpulsion rates may vary significantly between devices,but we have been unable to find any published evidenceestimating expulsion rate or pregnancy rate for this newIUD. Our results will provide some evidence of whetherthe new IUD is comparable with the current standard,and provide the first prospective rigorous evaluation ofeffectiveness at 1 year for post-abortion contraceptivemethods currently available in Canada.Nearly a third of Canadian women have at least oneabortion [1]. Annually about 100,000 abortions are per-formed in Canada [2]. In 2009, at least 30.7% of thesewere repeat abortions [3]. Women having repeat abor-tions are more likely to be from ethno-cultural minor-ities, to report problems with a male partner, to have alower level of education, and to have other children athome [4,5]. Thus, research to delineate methods to pre-vent recurrent unwanted pregnancies in this vulnerablepopulation is a high priority. Ames [6] found a 5-year re-peat abortion rate of 9.4% for Canadian women who hadan IUD (Flexi-T380(+)W; Prosan International BV.Arnhem, The Netherlands) [7] placed immediately aftera first-trimester abortion. However, this retrospectivestudy was only able to determine the recurrent abortionrate of women returning to the index abortion clinic;thus, it is possible that the number of pregnancies wassignificantly higher than the number of repeat abortionsreported. Even so, the reported repeat abortion rate of9.4% is significantly higher than would be expectedbased on evidence for the post-abortion effectiveness ofa copper IUD [8,9]. Overall 5-year pregnancy rate forIUD users is estimated to be less than 2% [10-12], or arepeat abortion rate of 35 per 1000 women-years offollow-up for women with other models of IUD placedpost-abortion [13]. Indeed, the placement of copper IUDtypes available in other jurisdictions as an effectivecontraception method following a first-trimester (before12 weeks of gestational age) abortion is well supportedby systematic reviews [8,14].The only copper IUDs available in Canada at the timethis study began were the Nova-T (Nova-T200W; Bayer Inc,Canada), and two Flexi-T devices (Flexi-T300W and Flexi-T380(+)W; both Prosan International BV) [7]. Canadianphysicians report higher rates of expulsion with the Flexi-Tdevices [6,15] and yet many prefer the Flexi-T380(+) be-cause evidence supports copper devices with a surface areaof 380 mm as being more effective than those with an areaof 200 mm [10,14,16-19]. We found no reports in theliterature describing the expulsion rates or effectiveness forthe Flexi-T devices, although reported outcomes forNovaT200 are available [16-19].This RCT will determine if the Flexi-T380(+) copperIUD (referred to hereafter as ‘FlexiT’) is comparable withthe most common Canadian copper IUD currently inuse, the NovaT-200 copper IUD (referred to as the‘NovaT’), when placed immediately after a first-trimesterabortion. Additionally, we will report the first rigorousevidence for the effectiveness of, and satisfaction with,the range of post-abortion contraceptive options availableto Canadian women.Methods/DesignStudy designThis prospective non-inferiority randomized controlledstudy will recruit women at the time of an abortion at ges-tational age of less than 12 weeks (first trimester). Con-senting women choosing to use an IUD post-abortion willbe randomized to type of device, and women choosingother post-abortion contraceptive methods, or no methodof contraception, will be enrolled in a non-intervention,observational arm. Primary outcome will be rate of expul-sion at 1 year. Secondary outcomes will include rates forpregnancy; complications such as infection or perforation;continuation of, and satisfaction with, the chosen contra-ceptive method as determined at 1, 2, 3, 4 and 5 years; andexpulsion rate for each type of copper IUD at 2, 3, 4 and5 years.Sample-size justification for comparing expulsion ratesfor the NovaT and FlexiTOur aim in this non-inferiority study is to provide evi-dence that the expulsion rate for the Flexi-T does notexceed that of the Nova-T by more than 10%. The ra-tionale for this choice rests on the assumption that thedetection rate for IUD expulsions is at least 85% [20],which implies that the loss in efficacy of a device due toexpulsions is less than 0.15 times its expulsion rate,and correspondingly, that any difference in efficacybetween devices is less than 0.15 times the differencein expulsion rates. Thus differences of 10% in expul-sion rates translate into differences in efficacy of 1.5%or less.We calculated power calculations for non-inferiority test-ing following the approach described by Blackwelder [21]using the on-line calculator provided by S. Patten [22].Our null hypothesis is:H0: FlexiT expulsion rate ≥ NovaT expulsion rate + 10%.This formula requires specification of the problem interms of success proportions (that is, those not experien-cing expulsion by 1 year). We will assume the rate ofthose not experiencing expulsion will be 96% for theNova-T [17-19] and 92% for the Flexi-T. Thus, weNorman et al. Trials 2012, 13:147 Page 2 of 6http://www.trialsjournal.com/content/13/1/147require a sample size of 192 per group to attain 80%power at α = 0.05 to detect a difference in expulsion ratesexceeding 10%. We will enroll a total of 400 women, a suf-ficient number to allow for changes to intention to leavethe province and thus loss to follow-up using the healthadministrative databases. This recruitment will ensure thefinal sample is at least the 384 women required to test thenull hypothesis that FlexiT has a significantly inferior(higher) expulsion rate compared with the NovaT.Thus, our recruitment will include 400 women whochoose to have IUDs and consent to be randomized toeither the Flexi-T (200 women) or the Nova-T (200women), and a further 200 who decide to not to useintrauterine contraception, who will be enrolled as anon-intervention comparator group. Therefore, a totalof 600 women will be recruited.The study clinic (see ‘Recruitment facility’, below) pro-vides abortions to about 700 women meeting the entrycriteria each year, and based on our previous research inthis setting [23] we expect 40% of eligible women tochoose an IUD, and 80% of these to enroll in IUDgroups. Target enrollment is anticipated at 22 months.Inclusion criteriaAll women at participating study sites who have com-pleted informed consent for an abortion at less than 12weeks gestational age (as determined by ultrasonography)and who are residents of the Canadian province of BritishColumbia (BC) enrolled in the universal provincial med-ical services plan are eligible to participate. Additionally,those who have chosen to use an IUD for post-abortioncontraception are eligible to be randomized to the devicegroups. The study has no minimum age criteria forenrollment.Exclusion criteriaWomen are not eligible if they intend to move from BCwithin the next year, if they intend to conceive within 1year, or if they are currently enrolled in another clinicaltrial. The contraindications to the use of an IUD are alsoexclusion criteria. Uterine cavity anomalies causing distortion of theendometrial canal including fibroids of more than 50mm, excluding repaired uterine septum. Wilson’s disease. Current untreated pelvic inflammatory disease,cervicitis, or lower genital tract infection. Undiagnosed abnormal uterine bleeding. Known uterine or cervical malignancy or cervicaldysplasia. Bacterial endocarditis. Established immunodeficiency (HIV positivity is notan exclusion unless immunodeficiency is present). Acute malignancies affecting blood or leukemias. Recent trophoblastic disease with raised levels ofhuman chorionic gonatotropin.Post-randomization exclusion factors for women inthe randomized groups include perforation or excessivebleeding at the time of their abortion, failure to undergothe abortion procedure for any reason, or a uterineanomaly detected at the time of the abortion procedure.These exclusions are designed to be only those that, inreal-life clinical practice, would preclude a woman frombeing able to use an IUD as an immediate method ofcontraception.Recruitment facilityRecruitment for this study will be undertaken at ateaching-hospital outpatient abortion service in theCanadian province of British Columbia (BC).Enrollment processAll women presenting at the study clinic for an abortionof a pregnancy before 12 weeks gestational age will re-ceive information via the research study web page [24]at the time they book their appointment, and a study in-formation brochure upon check-in. All women willundergo a post-abortion contraception information ses-sion with a trained clinic nurse who is not part of the re-search staff, and the women will decide upon theircontraceptive method of choice before they are asked ifthey wish to participate in the study. Interested potentialparticipants will then be referred for an information ses-sion with a trained women’s health research assistant(RA). The RA will explain all study procedures, answerall questions, and complete the informed consent processwith women before the time of their abortion, includingestablishing preferred personal contact methods to ensurefollow-up. Enrolled women will complete an intake ver-sion of the contraception satisfaction questionnaire (CSQ)on site. We have previously described the developmentand use of the CSQ [23]. Briefly, this is a detailed instru-ment eliciting the effectiveness of, degree of satisfactionwith, and adverse effects experienced for the range ofcontraceptive methods available in Canada. The CSQ hasbeen adapted from a published instrument [25,26] for usein post-abortion studies. It has been translated into thethree most common non-English languages in our studypopulation, and piloted for accuracy and cultural sensitiv-ity. This trial has been registered at ClinicalTrials.Gov(Identifier: NCT01174225).Participants choosing a copper IUD will be rando-mized to receive either the Flexi-T or the Nova-T. Strati-fied (that is, separate) randomization lists in sequentialblocks of sizes of eight will be generated for parousand nulliparous women. Allocation will be performedNorman et al. Trials 2012, 13:147 Page 3 of 6http://www.trialsjournal.com/content/13/1/147remotely using a Canadian on-line randomization service(http://www.randomize.net [27]), to maintain strict con-cealment. Staff will be kept unaware of the randomizationdesign and of stratification factors involved, to mitigatethe potential for unblinding of individual blocks. Forwomen choosing an IUD, the study device determined bythe randomization will be inserted by their surgeon imme-diately after the abortion and before the worman leavesthe procedure or operating room. Blinding of the surgeonor the woman receiving the IUD is not possible, as theIUDs are distinct in appearance. Even once in situ, thesetwo devices have a differing number and consistency ofstrings palpable at the cervical os. Following standardclinic protocol, all women will undergo PCR testing forchlamydia and gonorrhea before their abortion, and re-ceive 2 g metronidazole as a single observed dose asprophylaxis against postoperative infection [28]. Womendeemed to be at higher risk of a sexually transmitted infec-tion (STI) [28] and those with positive PCR results will re-ceive 1 g of azithromycin as well. A post-placementultrasound image of the IUD in situ will be recorded.Participants choosing no contraception and all othermethods of contraception will receive normal instruc-tions from the facility physician for implementation oftheir contraceptive method, undergo the same STI testingand prophylaxis protocol, and complete an intake CSQbefore leaving the abortion facility.Enrolled participants will complete the subsequentCSQ either by mail or as a web-based questionnaire at3, 6, and 12 months post-abortion. User-friendly inter-net-based and paper-based formats are available for eachof the four most common languages spoken in our studypopulation.All recruited women will receive reimbursement fortheir time in the form of a gift certificate at enrollmentand for each completed CSQ submitted. In addition,women choosing to be randomized to an IUD arm willreceive their device free of charge.Outcome determinationPrimary outcome determination will be through dataobtained from the provincial government health adminis-trative databases and from the CSQ to determine the ex-pulsion rate for each group at 1 year. Permission will beobtained from participants to use personal health numbers(the unique identifiers used in these databases) and date ofbirth to search these databases, detailing all subsequentcare received in BC within the subsequent year (includingIUD removals and re-insertions, and prescriptions for al-ternate forms of birth control; information on subsequentpregnancies such as miscarriages, abortions, or deliveries;and any hospital re-admissions, surgery or prescriptionsdispensed for antibiotics, which may indicate possiblecomplications). The CSQ will collect data on expulsion ofIUD, effectiveness of and satisfaction with the contracep-tive method and insertion timing assigned, any removal ofthe IUD, any change to contraceptive method or intentionto conceive, any interval pregnancies and their outcomes,and any adverse events. Using both the databases and theCSQ methods for outcome determination over a period of5 years (the device life for the IUDs) we will determine,with a close to perfect follow-up rate, the intention totreat (ITT) effectiveness of post-abortion contraception inCanada.Ethical considerationsThis study has received institutional review boardapproval from the University of British Columbia-Children’s and Women’s Research Ethics Board (H10-00798)and the Interior Health Authority Research Ethics Board(2010-034).AnalysisPrimary outcome will be examined as expulsion rate at 1year for women randomized to receive the FlexiT devicecompared with women randomized to a NovaT. Second-ary outcomes will be examined annually over the 5-yearperiod using an ITT framework for both randomizedand non-intervention groups, and will include: preg-nancy rate, rate for continuation of method, adverseevents (such as infection or perforation), outcomes ofthose participants who were chlamydia-positive at thetime of abortion, and satisfaction with contraceptivemethod chosen and expulsion rate for years 2 to 5.Analysis methodsBecause our aim is to examine expulsion rates and es-tablish the non-inferiority (within a margin of 10%) ofthe Flexi-T compared with the NovaT, the primary ana-lysis will be based on an upper (one-sided) 95% confi-dence limit for the difference in expulsion rates (FlexiTrate minus NovaT rate). Non-inferiority will be inferredif the confidence limit value is less than 10%. This sim-ple approach is valid so long as no systematic differencein follow-up occurs between groups. As a check, we willalso conduct analysis to account for partial follow-up.Because our outcome definition is essentially compositeand the relevant risk periods differ by components,Kaplan-Meier estimates for each component event willbe determined, and composite estimates will be obtainedby summing the estimated cumulative event rates (calcu-lated as 1 minus the survival function) at the time pointsindicated in our operational definitions. Confidenceintervals around the difference in these estimates will becalculated using the bootstrap method.Norman et al. Trials 2012, 13:147 Page 4 of 6http://www.trialsjournal.com/content/13/1/147Rates for all secondary outcomes will be calculated inan ITT framework for events occurring within 1year andwithin successive years following the abortion, and forpregnancy events, those associated with a conceptionwithin a year or successive years. Outcomes will bedetermined using the CSQ, direct access to clinicalfollow-up visit records, and billing and procedure codingdata from the administrative health-system databases.Multivariate logistic regression will be used to examinedemographic, socioeconomic, and obstetric factors in re-lationship to primary and secondary objectives.Survey analysisThe quantitative data from the CSQ will be analyzedusing descriptive and correlational statistics. The CSQcontains several scales, providing composite scores thatcan be used to indicate differences in the secondary out-comes. Open ended questions will be analyzed throughcontent analysis, focusing on key topics.DiscussionAnticipated limitationsChanges in intention to conceiveOwing to our exclusion criteria, we will recruit onlywomen who do not intend to conceive within the firstyear after enrollment. Nevertheless, in this study popula-tion with an anticipated mean age of 24 years, we fullyanticipate that some women will change their intent toconceive over the first and subsequent study years. Wewill account for this in two ways. First we ask at eachCSQ interview (3, 6, and 12 months) about the partici-pant’s intent to conceive, and second, we will assumethat randomization will distribute those who haveintended pregnancies within the study period evenly toboth arms of the study.ExpulsionsMost women will be aware when an IUD expulsionoccurs [20], and should it occur, will make arrangementsfor alternative contraception. This alternative contracep-tion may be a replacement device or a change in contra-ceptive method. Each participant will be provided with atoll-free number enabling them to contact the principalinvestigator (WVN) at any time. In addition, the studyteam will monitor follow-up visits, CSQs, governmentmedical plan billings, and prescription records of alter-native contraception prescribed or an IUD removed orinserted. In this manner, we believe we will be able to es-timate device expulsion rate with a fair degree of accur-acy. To reflect usual contraceptive conditions mostaccurately in the event of an expulsion, we are notproviding a free replacement device. We have stratified atrandomization for parity, as this may be a confoundingfactor in expulsion.ContributionThis is the first study to determine the expulsion rate forthe FlexiT380(+) IUD, and to determine if it is non-inferior to the standard IUD available in Canada, theNova-T 200, for post-abortion contraception. In addition,this study will provide the first ITT evidence on outcomesfor a wide range of contraceptive methods currently avail-able in Canada, including consumer satisfaction, methodcontinuation, and pregnancy rates at 1 year post-abortion.Understanding of satisfaction and effectiveness for com-mon contraceptive options will better inform efforts toprevent recurrent unintended pregnancy among Canadianwomen.Trial statusThis trial is currently open for enrollment, with the firstenrollments having commenced on 5 October 2010. En-rollment in the non-intervention group (those womennot choosing to use an IUD) has been slower thanexpected but full enrollment is anticipated in late 2012.AbbreviationsBC0: British Columbia a province in Canada; CSQ: Contraception satisfactionquestionnaires; FlexiT380 and Flexi T: Copper Intrauterine Device (“Flexi-T380(+)” W Prosan, The Netherlands); IUD: Intrauterine device; NovaT200 andNovaT: Copper Intrauterine Device (“Nova-T200” W Bayer Inc, Canada);PCR: Polymerase chain reaction; RCT: Randomized controlled trial;UBC: University of British Columbia; WHRI: Women’s health research institute.Competing interestsThe authors declare that they have no competing interests.Authors’ contributionsWN, JK, RB, CT, and JC made substantial contributions to conception anddesign of this study. WN and AA will contribute to acquisition of data, andall authors will contribute to the analysis and interpretation of data. WN, JK,RB, CT, JC and AA drafted the protocol and protocol manuscript, and allauthors contributed to critical revision for important intellectual content. Allauthors have read and approved the final manuscript.Authors’ informationAll authors work within the Contraception and Abortion Research Team ofthe University of British Columbia (UBC). This team is supported by theWomen’s Health Research Institute (WHRI) of British Columbia Women’sHospital and Health Centre, Vancouver, Canada. WVN was supported by theClinician Scholar's Program within the UBC Faculty of Medicine at the timeof study inception, and is currently supported as a “Strategic Training Fellowin Interdisciplinary Primary Health Care Research” by the Canadian Institutesof Health Research Strategic Training Program – TransdisciplinaryUnderstanding and Training on Research – Primary Health Care.Acknowledgements and fundingFunding for this study is primarily through a large grant from the Society ofFamily Planning (SFP) [29]. The views and opinions expressed are those ofthe authors and do not necessarily represent the views and opinions of SFP.Additionally, pilot study work was supported by a Sue Harris Family PracticeResearch Grant from the WHRI. Infrastructure support for this study isprovided by the WHRI, the Women’s Services Clinic of Kelowna GeneralHospital, Kelowna, BC, and the Department of Family Practice, Faculty ofMedicine, UBC.Author details1Contraception Access Research Team, Women’s Health Research Institute,Vancouver, British Columbia V6H 1G3, Canada. 2Department of FamilyPractice, University of British Columbia, Vancouver, British Columbia V6T 1Z3,Norman et al. Trials 2012, 13:147 Page 5 of 6http://www.trialsjournal.com/content/13/1/147Canada. 3School of Population and Public Health, University of BritishColumbia, Vancouver, British Columbia V6T 1Z3, Canada. 4Department ofStatistics, University of British Columbia, Vancouver, British Columbia V6H3V4, Canada. 5Département de médecine familiale et médecine d’urgence,L’Université de Montréal, Montréal, Quebec, Canada.Received: 16 July 2012 Accepted: 9 August 2012Published: 24 August 2012References1. Norman WV: Induced abortion in Canada 1974-2005: Trends over thefirst generation with legal access. Contraception 2012, 85(2):185–189.doi:110.1016/j.contraception.2011.06.009. http://www.contraceptionjournal.org/article/S0010-7824(11)00424-0/fulltext.2. Statistics Canada: Induced Abortions 2005. The Daily Wed May 21,2008.[Internet]. 2011. Available from: http://www.statcan.gc.ca/daily-quotidien/080521/dq080521c-eng.htm.3. 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The Netherlands: Health Canada Licence: 64100;2007.8. Stanwood NL, Grimes DA, Schulz KF: Insertion of an intrauterinecontraceptive device after induced or spontaneous abortion: A review ofthe evidence. BJOG 2001, 108(11):1168–1173.9. Bednarek PH, Creinin MD, Reeves MF, Cwiak C, Espey E, Jensen JT, Post-Aspiration IUD, Randomization (PAIR) Study Trial Group: Immediate versusdelayed IUD insertion after uterine aspiration. N Engl J Med 2011,364(23):2208–2217.10. Thonneau PF, Almont TE: Contraceptive efficacy of intrauterine devices.AJOG 2008 Mar, 198(3):248–253.11. Blumenthal PD, Voedisch A, Gemzell-Danielsson K: Strategies to preventunintended pregnancy: increasing use of long-acting reversiblecontraception. Hum Reprod Update 2011, 17(1):121–137.12. ESHRE Capri Workshop: Intrauterine devices and intrauterine systems.Hum Reprod Update 2008, 14(3):197–208.13. Goodman S, Hendlish SK, Reeves MF, Foster-Rosales A: Impact ofimmediate post abortal insertion of intrauterine contraception on repeatabortion. Contraception 2008, 78(2):143–148.14. Grimes DA, Lopez LM, Schulz KF, Stanwood N: Immediate postabortalinsertion of intrauterine devices. Cochrane Database Syst Rev 2007,4:CD001777.15. Medical Rounds Discussion: Post-Abortion Contraception. British Columbia,Canada: Department of Family Practice, Kelowna General Hospital, Kelowna;2009.16. O’Brien PA, et al: Copper-containing, framed intrauterine devices forcontraception: a systematic review of randomized controlled trials.Contraception 2008, 77:318–327.17. United Nations Development Program: Long-term reversiblecontraception: Twelve years of experience with the TCu380A andTCu220C. Contraception 1997, 56:341–352.18. Baeyertz JD, Hartfield VJ: The Nova-T 200 intrauterine contraceptivedevice: a 12 year study. N Z Med J 1997 May 9, 110(1043):169–171.19. World Health Organization Task Force on Intrauterine Devices for FertilityRegulation: IUD Insertion following Termination of Pregnancy: A ClinicalTrial of the TCu220C, Lippes Loop D, and Copper 7. Stud Fam Plann 1983,14(4):99–108.20. Neuteboom K, de Kroon CD, Dersjant-Roorda M, Jansen FW: Follow-upvisits after IUD-insertion: Sense or nonsense? A technology assessmentstudy to analyse effectiveness of follow-up visits after IUD insertion.Contraception 2003, 68(2):101–4.21. Blackwelder WC: “Proving the null hypothesis” in clinical trials. Control ClinTrials 1982, 3:345–353. Pubmed ID 7160191.22. Patten S: Sample Size for an Equivalence Study: Sample Size Calculator.University of Calgary. 2012. [Internet] Available at: www.ucalgary.ca/~patten/blackwelder.html.23. Norman WV, Kaczorowski J, Soon JA, Brant R, Bryan S, Trouton K, Dicus L:Immediate vs. Delayed Insertion of Intrauterine Contraception afterSecond Trimester Abortion: Study Protocol for a Randomized ControlledTrial. Trials 2011, 12:149. doi:doi:10.1186/1745-6215-12-149. http://www.trialsjournal.com/content/12/1/149 PUBMED id: 21672213.24. Norman WV: The Better Contraceptive Choices Studies: Contraceptionand Abortion Research Team. Accessed July 25 2012, web site. [Internet]Available at: https://www.bcc4me.ca/study2.aspx.25. Colwell HH, Mathias SD, Cimms TA, Rothman M, Friedman AJ, Patrick DL:The ORTHO BC-SAT – a satisfaction questionnaire for women usinghormonal contraceptives. Qual Life Res 2006, 15:1621–1631.26. Mathias SD, Colwell HH, LoCoco JM, et al: ORTHO birth control satisfactionassessment tool: assessing sensitivity to change and predictors ofsatisfaction. Contraception 2006, 74:303–308.27. Willan AR: Randomize.net [internet]. Ottawa: Biometrix Helath ResearchServices, Inc; 2012. Available from: http://www.randomize.net/index.html.28. Montgomery CA, Norman WV, Money DM, Rekart ML: Antibiotic prophylaxisat the time of induced abortion. BC Medical J 2002, 44(7):367–373. Availableat: http://www.bcmj.org/article/antibiotic-prophylaxis-time-induced-abortion.29. The Society of Family Planning: Research and Grants. Society of FamilyPlanning Web Site. 2012. [Internet] Available at: http://www.societyfp.org/research/applying.asp.doi:10.1186/1745-6215-13-147Cite this article as: Norman et al.: Comparing the effectiveness of copperintrauterine devices available in Canada. Is FlexiT non-inferior to NovaTwhen inserted immediately after first-trimester abortion? Study protocol fora randomized controlled trial. Trials 2012 13:147.Submit your next manuscript to BioMed Centraland take full advantage of: • Convenient online submission• Thorough peer review• No space constraints or color figure charges• Immediate publication on acceptance• Inclusion in PubMed, CAS, Scopus and Google Scholar• Research which is freely available for redistributionSubmit your manuscript at www.biomedcentral.com/submitNorman et al. 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