{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,16]],"date-time":"2025-12-16T12:33:50Z","timestamp":1765888430292,"version":"3.40.5"},"reference-count":19,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2020,9,28]],"date-time":"2020-09-28T00:00:00Z","timestamp":1601251200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["obgyn.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Aust NZ J Obst Gynaeco"],"published-print":{"date-parts":[[2021,2]]},"abstract":"<jats:sec><jats:title>Background<\/jats:title><jats:p>The diagnosis of a pregnancy of unknown location (PUL) is made when there is an elevated serum \u03b2 human chorionic gonadotropin (\u03b2hCG) and no pregnancy on transabdominal and transvaginal ultrasound. Most of these pregnancies end as intra\u2010uterine pregnancies or unsuccessful pregnancies and can be safely managed expectantly. However, up to 20% of these women will have an ectopic pregnancy. Several mathematical models, including the M4 and M6 protocols, have been developed using biochemical markers to triage PUL presentations. This rationalises numbers of tests and visits made without compromising safety and allowing timely intervention.<\/jats:p><\/jats:sec><jats:sec><jats:title>Aims<\/jats:title><jats:p>We aimed to externally validate the M4 and M6 models in an Australian tertiary early pregnancy assessment service (EPAS).<\/jats:p><\/jats:sec><jats:sec><jats:title>Materials and Methods<\/jats:title><jats:p>We performed a retrospective single\u2010centre cohort study across five\u00a0years. Our study population included all women attending our EPAS with a PUL who had at least two serum \u03b2hCG levels and one progesterone level measured. The M4 and M6 models were retrospectively applied.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Of the 360 women in the study population, there were 26 confirmed ectopic pregnancies (7.2%) and six persisting PULs (2%). The M4 model had a sensitivity and specificity of 72%. The M6P model had a sensitivity of 91% and specificity of 63%. The M6P misclassified two ectopic pregnancies into the low\u2010risk group, compared with seven in the M4 model.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>The M6P model has the highest sensitivity of the three models and a negative predictive value of 99%. These numbers are comparable to the original United Kingdom population. Further prospective validation is planned.<\/jats:p><\/jats:sec>","DOI":"10.1111\/ajo.13252","type":"journal-article","created":{"date-parts":[[2020,9,28]],"date-time":"2020-09-28T13:35:06Z","timestamp":1601300106000},"page":"100-105","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["How do the M4 and M6 models perform in an Australian pregnancy of unknown location population?"],"prefix":"10.1111","volume":"61","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3347-964X","authenticated-orcid":false,"given":"Sara","family":"Ooi","sequence":"first","affiliation":[{"name":"RPA Women and Babies Royal Prince Alfred Hospital Sydney Local Health District Sydney New South Wales Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5620-0170","authenticated-orcid":false,"given":"Bradley","family":"De Vries","sequence":"additional","affiliation":[{"name":"RPA Women and Babies Royal Prince Alfred Hospital Sydney Local Health District Sydney New South Wales Australia"},{"name":"Faculty of Medicine and Health The University of Sydney School of Public Health University of Sydney Sydney New South Wales Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Joanne","family":"Ludlow","sequence":"additional","affiliation":[{"name":"RPA Women and Babies Royal Prince Alfred Hospital Sydney Local Health District Sydney New South Wales Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2020,9,28]]},"reference":[{"key":"e_1_2_6_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.bpobgyn.2009.01.008"},{"key":"e_1_2_6_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.fertnstert.2010.09.006"},{"key":"e_1_2_6_4_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1471-0528.2011.03097.x"},{"key":"e_1_2_6_5_1","doi-asserted-by":"publisher","DOI":"10.1093\/humupd\/dmt047"},{"key":"e_1_2_6_6_1","doi-asserted-by":"publisher","DOI":"10.1002\/uog.2838"},{"key":"e_1_2_6_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.fertnstert.2012.09.012"},{"key":"e_1_2_6_8_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ejogrb.2012.07.020"},{"key":"e_1_2_6_9_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1471-0528.2011.02893.x"},{"key":"e_1_2_6_10_1","doi-asserted-by":"publisher","DOI":"10.1002\/uog.4015"},{"key":"e_1_2_6_11_1","doi-asserted-by":"publisher","DOI":"10.1002\/uog.15864"},{"key":"e_1_2_6_12_1","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/deu045"},{"key":"e_1_2_6_13_1","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/dew105"},{"key":"e_1_2_6_14_1","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.h5527"},{"key":"e_1_2_6_15_1","unstructured":"ViewPoint system GE. Webpage [Accessed 10\/01\/2020.] Available form URLhttps:\/\/www.gehealthcare.com.au\/products\/ultrasound\/ultrasound\u2010it\/viewpoint\u20106\u2010for\u2010mfm"},{"key":"e_1_2_6_16_1","doi-asserted-by":"publisher","DOI":"10.1046\/j.1442-2026.1999.00041.x"},{"key":"e_1_2_6_17_1","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/deq217"},{"key":"e_1_2_6_18_1","doi-asserted-by":"publisher","DOI":"10.1002\/uog.20420"},{"key":"e_1_2_6_19_1","first-page":"1","article-title":"Rationalizing the management of pregnancies of unknown location: Diagnostic accuracy of human chorionic gonadotropin ratio\u2010based decision tree compared with the risk prediction model M4","author":"Nadim B","year":"2019","journal-title":"Acta Obstet Gynecol Scand"},{"key":"e_1_2_6_20_1","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/des440"}],"container-title":["Australian and New Zealand Journal of Obstetrics and Gynaecology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/ajo.13252","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1111\/ajo.13252","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/obgyn.onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/ajo.13252","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,9,2]],"date-time":"2023-09-02T13:03:08Z","timestamp":1693659788000},"score":1,"resource":{"primary":{"URL":"https:\/\/obgyn.onlinelibrary.wiley.com\/doi\/10.1111\/ajo.13252"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,9,28]]},"references-count":19,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2021,2]]}},"alternative-id":["10.1111\/ajo.13252"],"URL":"https:\/\/doi.org\/10.1111\/ajo.13252","archive":["Portico"],"relation":{},"ISSN":["0004-8666","1479-828X"],"issn-type":[{"type":"print","value":"0004-8666"},{"type":"electronic","value":"1479-828X"}],"subject":[],"published":{"date-parts":[[2020,9,28]]},"assertion":[{"value":"2020-05-23","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2020-08-20","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2020-09-28","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}