{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,2]],"date-time":"2026-03-02T22:23:00Z","timestamp":1772490180445,"version":"3.50.1"},"reference-count":39,"publisher":"Wiley","issue":"8","license":[{"start":{"date-parts":[[2025,6,2]],"date-time":"2025-06-02T00:00:00Z","timestamp":1748822400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004257","name":"Helse Vest","doi-asserted-by":"publisher","award":["F\u201012156\/4800003677"],"award-info":[{"award-number":["F\u201012156\/4800003677"]}],"id":[{"id":"10.13039\/501100004257","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000066","name":"National Institute of Environmental Health Sciences","doi-asserted-by":"publisher","award":["Z01ES103333"],"award-info":[{"award-number":["Z01ES103333"]}],"id":[{"id":"10.13039\/100000066","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["obgyn.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Acta Obstet Gynecol Scand"],"published-print":{"date-parts":[[2025,8]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Introduction<\/jats:title><jats:p>Randomized trials have shown that progesterone treatment in mothers with a short cervix may reduce the risk of preterm birth, but the optimal time window for treatment remains unknown. We aimed to investigate progesterone treatment for the prevention of preterm birth by gestational age at diagnosis and initiation of treatment.<\/jats:p><\/jats:sec><jats:sec><jats:title>Material and Methods<\/jats:title><jats:p>This was a population\u2010based historical cohort study of 1162 mothers with singleton pregnancies diagnosed with a cervix &lt;20\u2009mm from 16 to 31 gestational weeks receiving progesterone treatment (<jats:italic>n<\/jats:italic>\u2009=\u2009390) or no preventive treatment (<jats:italic>n<\/jats:italic>\u2009=\u2009772). Data were collected from the Medical Birth Registry of Norway from 2014 to 2020 and linked to national health registries providing demographic, diagnostic, and prescription information. Risks of preterm birth &lt;28, &lt;34, and &lt;37 gestational weeks were compared between mothers with and without progesterone treatment in the full study sample and in three periods of gestational age at diagnosis (16\u201321, 22\u201327, and 28\u201331\u2009weeks) using log\u2010binomial regression analyses.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>The absolute risk of preterm birth &lt;28 gestational weeks was 0.8% in mothers treated with progesterone and 3.4% in mothers who did not receive treatment (adjusted relative risk (aRR) 0.25, 95% confidence interval (CI) 0.08\u20130.81). The strongest protective association was observed in mothers diagnosed from 16 to 21\u2009weeks (aRR 0.13, 95% CI 0.02\u20130.98). Preterm birth &lt;34\u2009weeks occurred in 8.7% of mothers in the progesterone group and 11.1% in the untreated group (aRR 0.80, 95% CI 0.54\u20131.17), and the relative risk reduction associated with treatment diminished with increasing gestational age at diagnosis: aRR 0.27 (95% CI 0.08\u20130.96) from 16 to 21\u2009weeks; aRR 0.68 (95% CI 0.38\u20131.23) from 22 to 27\u2009weeks; and aRR 1.30 (95% CI 0.71\u20132.39) from 28 to 31\u2009weeks. There was no difference in the risk of birth &lt;37\u2009weeks in mothers treated with progesterone (23.1%) and untreated mothers (22.3%), and the risk estimates were similar in the three periods of gestational age at diagnosis.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>Compared to no treatment, progesterone treatment is associated with a reduced risk of preterm birth &lt;28 gestational weeks in pregnancies with a short cervix. The preventive effect of treatment may extend to 34\u2009weeks if treatment is initiated early in the second trimester.<\/jats:p><\/jats:sec>","DOI":"10.1111\/aogs.15147","type":"journal-article","created":{"date-parts":[[2025,6,3]],"date-time":"2025-06-03T01:40:33Z","timestamp":1748914833000},"page":"1443-1451","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Timing of progesterone treatment to prevent preterm birth in pregnancies with a short cervix: A population\u2010based historical cohort study"],"prefix":"10.1111","volume":"104","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2972-4868","authenticated-orcid":false,"given":"Anders","family":"Einum","sequence":"first","affiliation":[{"name":"Department of Clinical Science University of Bergen  Bergen Norway"},{"name":"Department of Obstetrics and Gynecology Haukeland University Hospital  Bergen Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Roy Miodini","family":"Nilsen","sequence":"additional","affiliation":[{"name":"Faculty of Health and Social Sciences Western Norway University of Applied Sciences  Bergen Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Quaker E.","family":"Harmon","sequence":"additional","affiliation":[{"name":"National Institute of Environmental Health Sciences  Durham North Carolina USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Linn Marie","family":"S\u00f8rbye","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology Haukeland University Hospital  Bergen Norway"},{"name":"Faculty of Health and Social Sciences Western Norway University of Applied Sciences  Bergen Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nils\u2010Halvdan","family":"Morken","sequence":"additional","affiliation":[{"name":"Department of Clinical Science University of Bergen  Bergen Norway"},{"name":"Department of Obstetrics and Gynecology Haukeland University Hospital  Bergen Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2025,6,2]]},"reference":[{"key":"e_1_2_13_2_1","volume-title":"Born Too Soon: the Global Action Report on Preterm Birth","author":"WHO","year":"2012"},{"key":"e_1_2_13_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(08)60136-1"},{"key":"e_1_2_13_4_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(08)60074-4"},{"key":"e_1_2_13_5_1","doi-asserted-by":"publisher","DOI":"10.1177\/1403494816653288"},{"key":"e_1_2_13_6_1","doi-asserted-by":"publisher","DOI":"10.1177\/1403494821992894"},{"key":"e_1_2_13_7_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJM199602293340904"},{"key":"e_1_2_13_8_1","first-page":"902","article-title":"Sonographic measurement of uterine cervix at 18\u201022\u2009weeks' gestation and the risk of preterm delivery","volume":"92","author":"Taipale P","year":"1998","journal-title":"Obstet Gynecol"},{"key":"e_1_2_13_9_1","doi-asserted-by":"crossref","DOI":"10.1136\/bmj-2021-064547","article-title":"Interventions to prevent spontaneous preterm birth in women with singleton pregnancy who are at high risk: systematic review and network meta\u2010analysis","volume":"376","author":"Care A","year":"2022","journal-title":"BMJ"},{"key":"e_1_2_13_10_1","doi-asserted-by":"crossref","DOI":"10.1136\/bmj-2023-077033","article-title":"Cervical pessary versus vaginal progesterone in women with a singleton pregnancy, a short cervix, and no history of spontaneous preterm birth at less than 34\u2009weeks' gestation: open label, multicentre, randomised, controlled trial","volume":"384","author":"Dijk CE","year":"2024","journal-title":"BMJ"},{"key":"e_1_2_13_11_1","doi-asserted-by":"publisher","DOI":"10.1002\/ijgo.13852"},{"key":"e_1_2_13_12_1","doi-asserted-by":"publisher","DOI":"10.1002\/uog.26093"},{"key":"e_1_2_13_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ajog.2016.11.1037"},{"key":"e_1_2_13_14_1","doi-asserted-by":"publisher","DOI":"10.1111\/aogs.12622"},{"key":"e_1_2_13_15_1","doi-asserted-by":"publisher","DOI":"10.1002\/uog.17556"},{"key":"e_1_2_13_16_1","doi-asserted-by":"publisher","DOI":"10.1111\/1471-0528.16582"},{"issue":"7","key":"e_1_2_13_17_1","article-title":"Prenatal administration of progesterone for preventing preterm birth in women considered to be at risk of preterm birth","volume":"2013","author":"Dodd JM","year":"2013","journal-title":"Cochrane Database Syst Rev"},{"key":"e_1_2_13_18_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(21)00217-8"},{"key":"e_1_2_13_19_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(16)00350-0"},{"key":"e_1_2_13_20_1","doi-asserted-by":"publisher","DOI":"10.1111\/1471-0528.16544"},{"key":"e_1_2_13_21_1","unstructured":"MichelsenTM EllingsenL SalvesenKA Sj\u00f8borgK.Truende for tidlig f\u00f8dsel. 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