CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="390"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "gut.bmj.com",cType: 'managed',cRay: '91349442ae26252c',cH: 'HPSm7bUW1GbiZhGLBUtfAjzebE2ImCUGzqtKVqW4o5Y-1739782743-1.2.1.1-vQ2DDaK3CbWx5.YdYmh9GadNRLP4LCDpU8rAlMpiz.QIh.gM56Bq0AZgfk_7nNZQ',cUPMDTk: "\/?__cf_chl_tk=3X3djnF3ftJH55IFWeMk5qrOt99nhW1a2tjVc_GmlKw-1739782743-1.0.1.1-RwZ6omyMw8jq59u02vakzS_50XzcKC.Ua2aaw7oTvmE",cFPWv: 'b',cITimeS: '1739782743',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/?__cf_chl_f_tk=3X3djnF3ftJH55IFWeMk5qrOt99nhW1a2tjVc_GmlKw-1739782743-1.0.1.1-RwZ6omyMw8jq59u02vakzS_50XzcKC.Ua2aaw7oTvmE",md: "05I9AKdnAd5rlvyJ0jpwQYIAvrOVQMJXDX531hp0wOc-1739782743-1.2.1.1-lvIQ8t2UFiIqMRk_gnfUoHcpSzkZpPYodwLwyI3hxBEpH2KrjzzoWKfOTZZA3N1omP99CEGhaEPnIHMH_OFZAuZOsOFi_u5YkebFon4R5hnlM9u2W3UslL32h9RyHMZq7Fb.KKnfg3gZ1q5bJTnwTK5LYHGlMrzpIloKnifGPViDMs1nySccaTTVOKRorypOpS5g4UQCaK6J_OqmtBTl6RPzx09vFkLY1Veduwve2GGTewlXHZzDPZasMmqoGPfonbmudUcxusPpAPLuTWcCi4YMFA97Gj_aCWZBjgM0Aj1B7rR27Kf4jbxheeMYRWY43917fy3hwmXBbe8lems8HZg_ouU3KkYqTKvr4Dvld6coTOCAEfNg._ZEoYfhCwRYX82vdcNb2aDlCmylUqzAJyl6wv68pHNsheA6fsa9TGDcdIUNaRbMLiUVznB3hNDFF22l2C9xfVa3tAgggMH29VcaNVrj0ISUOYICCiAJR7SSp0NQ7O.gYWmlhJSi40MKjlrtx4F5z3MNwAG0cQ7k1dfwFolCqVFE1uZY5H_7isIaQPHqidsm3.lVKjhuF6L30FCnlNk._l6Y9NksvPBY8OQeWHeQMB596Zrxc6yxKr8Wk.8IRKodxRY7C97KhPKbVoAjX4SHVs5qdN3ZNNb5g1LZAzLBzrVV1vZkT5cEmDWZaTX7f.BM.w9xcJI2iB7CKgx4t4WWSkGZUioc0m3JhKajL8vuT59RyL7zcOvsf89zi93kqzNpjkaEQ88q85hDEntNavG3JhBpsTGyITJIYpqsGK0._fLzSVLFqf.HgKP8Os4_d2eiWIWUjkLrbr05ItoNY4ywgH6YaEyEHV9v.cH7rCVpC8h877MaHvw.SQtStVXhS7ZyDOcSBQDwInCJzwKEgSFWKRxMVMGj39IkGxlH5kxczQyzc3gOFByLvKPvloEtfitZC8kL3PLHQJU_YwH1oKTXsLpjhXjjLsXEv8lqz_1ZOmDNpPSByskKsE19vx_iIs664hyGcGKmgA0Io8CJDIBaPphoMnr7uTC8xfVVOqws8vk0rQOdEGN5.QPdPVpzt6IxxQV0axrAAoiFJzztmXN.uakaCK24dUeSG8ug_7x5qiwya1Hr20Uo36PL4lPJJ730IalPHomX.rd3s7YdtaKngYhmp7O5bpENLXHYbo7cO3sdETQR7QSYulmFna.yymWuHB2BSBsKvDiq0WozQ4MXe0vElNBuXK2bMalaosW8le.DVVWx40Mcc3sOsBpJmBzjO4Ts17tYDnMRHuKGUhZl6myQOJabi1EQWDvu00UovKNIBiGnTslLnOGYOAPtwOvQgi6k0JbRVoC48JmPlv5yhOFX0pBbdWKLSjkMh74ffyWyGwe5_HBJ1CjcD.EUARUgznpAjmeefQMHhvZny7ptJ5tkBSh85Pi1UyjtFqIulmfW4PJojtiRWlJ598zrmadHueGNXTpLolcVkEPhMAoWVHyDRERzfw4DQfTKZIqDGIgdMWkECktt5IKqZCADOg4SvLS17J.z3sZd4s.t30LPkMesZQu1pP7oUHRxOiB310nItzvoi3f_5NdwFXEsaLBW9dEg_aPTwQsqOLZ4Vm50Zatkj.QFXLnThtS17U.6_nJP9glYICnzqTWbRBRel_HrpPZOmoPXwqxqVL1c1Xvf.IHA_7GXsIqxFz_PFV5DHD8vOiixPBA31chJdN0lDProQXUOm4.HAIvxNR3XYKontlRiRB9p3VsAi9HfIvUzxA025Xjl9R5hRxHxbxJwTV_ZaOmgvM_oqrccv7rzGveIUT0OL5zYYiaWCdJO1c5xzMoi6vjc2MwK2djOqeSPaJHeR5ZE.9AS4bvdk7NHZNgtF6D2i24Ebz4zVOG4LteCBWZPvZfrrzWOnu6c3GtmDJcgMc6_R6qNksPsGQrNrwUv1wlG3QbBRBHhd_kKZ8MuFrkeKeoWDThQLopmRBHKCwdIeW6K_OhbvJ_flzoUEWD2ihD45PNmjv_bUQ2z1bhLL.fMCxcmgrVXH.MAN7tNyRWK8erRWx2hIcY9nlN0GnX.hZ43yqy7FEaYOCjWI.NS_Ex.904aX9NUx8iHrEwX9YnBT0tfqI8zTqWIEMOFe60nYfxNB6NqcT.hHDRYam1J2HgBuaYbx2wRfiThjXP3n0CBcrCRKlNWaStOKWDKNOIbue3gZribgMWyNof0NbxLTboXZ1HWXJUjJK01L4SQ0YFb5Z3nHIB0EPLwFghZvO7b5cXgisOFpFx_Bljb0F1Df2rVQVYxXaX3P.o31RxmZvaxclm_jyNQpvK5ly8SgFqryFHkHyC2FUk.rqPCPszxGLR_fMKKfPbjclGcYQIz5KvaiZmFKlgCPIefzt5n1UxzHOsKWCMrcdSFNRwoyUtWhnsKHLuZYl66iGVsZ.qyJaT4N0gPqLo3uapTr22g_2ctYDKuzZYSRAMesw",mdrd: "iNTvjXT16Tk6EjTwwA9rWfRGKgiw_KgG4tjpuK8uXto-1739782743-1.2.1.1-9MZAxBtqax7sc6ymVuDVchjUS.WxNoVCbh6xgZtxpLPabHch9i10QIikx6yhgPq9tmqAUg.WVwLHxs7U_eewe0.fm7L.Fq_LATx19fDeeAuoOP7LJd8JYduV7BeNkO59wKLoOnRpaoBdDeyK098V.4jAAXGSHvoxkm.tR6R94GqB_dbr0kYtcTnh6BUeSXGjEa4nMXiv6MhvCuiAtSLuZtprKMGXCgBbTUnZTyAPCZndf8TWgXpbhR7mVkY9qBx1_1yN5DWG921ID1PWPlocFQ2zQjOx..BZUP8CtReKRHXZSHW2up9pPAEBvZjZK1olAK5s7y7.Yoh75kTyk_2RykY3ANngK0hGoYHcxosTg_jHMxomOGDS.pcFifApfZ_kumFHQve05ig1x3S5WMjQCuIMKlXj4Dgs3.gnja7le_gCI6lO2HarYzY1EVAudjeOwC9rEY_.5H14fueHE_jjTsOkR4WtY71YBAV7uSRd4QLLHEyFbmmfi2mgKHQSyP.jiYn.5YcvbxB1RdsEjK4ZE6Px7uPsBd3on2OgQuuMGt0sup.b4ns1SEnN0LgMn7Ly4L60lNnke3QcqxYWMz0K3JE362TxoDAAPxEvhmNP.HKnA939PF2npssoqCOtSHxqB4ktcNiCOxDJy_mfr3KbaxI6PMnSrVLEfp3fZHAbgGyatn80EtvRbTvvxQfbZuewXyry2NZKwgO.J8MjWxVPul1AV4qEFcyWCwsmrX_yiSeOmFG6Ak0CggK50ltjv2pC8DDbapeKPGM2MXGTsdoQYbGfWor7e9deefYHeRhxAWnbGcGSK4ub_RT_MI.UogRy733jK_RLqhbJM_ox3g1yxbh4JeZyvW8kbDY8AHLoDodgAFyF4M4NRfsXniYJWDxjwaLqkNF1rGF9jAv58QPw6pQ4NL8FhTEBK1rF3AoM7CnBszl_a7HwzXHs0t.jWlvgSJU6FReS6dZcM4gfGPlj.oqm2qVu3OhkCQOidqM0nmh3FMCqyt2mZW87UxcZIiRUdFKBI.4M6jB1Ik7cUVgaLz0enuld6uQUHc0cS4Fjpx9XuDj3bnLNTtdhvhx6zU3eH3s.5.zKvP905hwkRd93tUHeOPUD.BPIZOoyylABPlwA1wtKdfjGeifBxojnmKke24f2MWuAr2oWWEgcOI0j5_wpTCoaxbl.cvUoqI1wU_gEDMJ8daJfzEuuD_mVClzUC1HKlKwmEwuWfpKkn81k6DRzU7DCL_aMKqBXUHjA9ZJMk1mcHBEmeijNXCj0v67vklwiZM3bgxP83bdMmPSp0SvV3nXv4UQC6332k6E0GJIkXhet3UfhgTKJSYW_VOlDpEKrm4JkwBmc.goN6ZvCU9_ptvqjstIb66452VIbRMfjB9cGEQ24fvMvWU7.qFsKg.Td_KWLNg1YB5ECyf.aEWbICIgdR6Es7vMb9ShGU2rfLEUdHh6SqXc79bm1erRHmECqemVuWvsVhnSw._UYPtuan05bOwwZlOveH5TmWwmkb0Rt.V.XgAPO3NFqjFoY7gSnIqbyLRyri7PpQvR6D8eemuoXGMbxX2.Ot31XCRB04IkTbZm1vfYDkVBhIOQUWDRsREhyV_bMJxEhT2Wx3qzDgeOBdrcRDlIriE4npvGE4o1_NlFBrS6rbS5_rkEGXBWE4U_3ZQ.DfGdBGgXysdCMvGsUi_ZqPRP8IUyy6XueZyHkVxGeeRO84Q9kBbH.vJSfdz_ouYN50ujc0z9RRC7cxG0b6mqtHGjYNgCchkg2XqQmxOAzhmhl3Wi0qDQJvRTsrRoDIP2hzPVjBSlQ6dhvSmlcDNbZJFFJFFNUn2KcN6NacIXQWaseXdSwW4kdJ4LX1JkkrqLm6FJS2_.MFmYo3eBeMTtF4timVlTIfcuRaJ5BI.1D08kUitKFSXlAStUtEQjkhI_RjOU91ogZ7GOZgj.o_j4a4duTNIEsHPQ"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=91349442ae26252c';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/?__cf_chl_rt_tk=3X3djnF3ftJH55IFWeMk5qrOt99nhW1a2tjVc_GmlKw-1739782743-1.0.1.1-RwZ6omyMw8jq59u02vakzS_50XzcKC.Ua2aaw7oTvmE" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>