{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,1]],"date-time":"2026-09-01T06:57:02Z","timestamp":1788245822800,"version":"build-2803163510"},"reference-count":21,"publisher":"Wiley","issue":"9","license":[{"start":{"date-parts":[[2025,4,21]],"date-time":"2025-04-21T00:00:00Z","timestamp":1745193600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["obgyn.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["BJOG"],"published-print":{"date-parts":[[2025,8]]},"abstract":"<jats:title>ABSTRACT<\/jats:title><jats:sec><jats:title>Objective<\/jats:title><jats:p>To compare the effect of luteal\u2010phase progesterone supplementation in natural cycles to expectant management on live birth rates in women with unexplained infertility (UI).<\/jats:p><\/jats:sec><jats:sec><jats:title>Design<\/jats:title><jats:p>An open\u2010label, parallel\u2010arm, single\u2010centre randomised controlled trial.<\/jats:p><\/jats:sec><jats:sec><jats:title>Setting<\/jats:title><jats:p>One tertiary NHS\u2010funded fertility unit.<\/jats:p><\/jats:sec><jats:sec><jats:title>Population<\/jats:title><jats:p>Couples with UI for at least 1\u2009year.<\/jats:p><\/jats:sec><jats:sec><jats:title>Method<\/jats:title><jats:p>A comparison of luteal phase micronised vaginal progesterone treatment (400\u2009mg bd) with timed intercourse and timed intercourse alone for 3\u2009cycles.<\/jats:p><\/jats:sec><jats:sec><jats:title>Main Outcome Measures<\/jats:title><jats:p>Primary outcome: Livebirth rate. Secondary Outcomes: Biochemical pregnancy, clinical pregnancy, mid\u2010luteal serum progesterone and pregnancy loss.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>One hundred and forty\u2010three couples were randomised. Livebirth rates were 11\/72 (15.3%) in the treatment group versus 5\/71 (7.0%) in the control group (RR 2.17, 95% CI 0.79\u20135.93). Biochemical pregnancy rates were 15\/72 (20.8%) versus 10\/71 (14.1%), (RR 1.48, 95% CI 0.72\u20133.07) and clinical pregnancy rates were 14\/72 (19.4%) versus 9\/71 (12.7%), (RR 1.53, 95% CI 0.71\u20133.31) in the treatment and control groups respectively. Pregnancy losses: 4\/15 treatment group versus 5\/10 control group (RR 0.53, 95% CI 0.19\u20131.51). One biochemical pregnancy loss in each group and 2\/15 miscarriages in the treatment group versus 3\/10 in the control group. Total miscarriage rates including biochemical losses were 3\/15 (20%) versus 4\/10 (40%) (RR 0.5, 95% CI 0.14\u20131.77).<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>The results did not reach statistical significance. However, the difference in livebirth rates warrants further investigation as this simple, noninvasive, inexpensive treatment would be a very attractive option for affected couples. A larger trial using the effect size from this study to guide sample size is planned.<\/jats:p><\/jats:sec><jats:sec><jats:title>Trial Registration<\/jats:title><jats:p>The PiNC trial was registered with the EU Clinical Trials Register on 29\/11\/2019 <jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"http:\/\/www.clinicaltrialsregister.eu\/ctr-search\/search?query=homerton\">www.clinicaltrialsregister.eu\/ctr\u2010search\/search?query=homerton<\/jats:ext-link>. The first participant was recruited on 25\/2\/2020.<\/jats:p><\/jats:sec>","DOI":"10.1111\/1471-0528.18171","type":"journal-article","created":{"date-parts":[[2025,4,22]],"date-time":"2025-04-22T00:24:05Z","timestamp":1745281445000},"page":"1220-1227","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Progesterone Luteal Support in Natural Cycles for Unexplained Infertility: A Randomised Controlled Trial (The <scp>PiNC<\/scp> Trial)"],"prefix":"10.1111","volume":"132","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2969-2437","authenticated-orcid":false,"given":"Claudia","family":"Raperport","sequence":"first","affiliation":[{"name":"Women's Health Research Unit Wolfson Institute of Population Health, Queen Mary University of London  London UK"},{"name":"Whittington Health NHS Trust  London UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elpiniki","family":"Chronopoulou","sequence":"additional","affiliation":[{"name":"Centre for Reproductive and Genetic Health  London UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aviva","family":"Petrie","sequence":"additional","affiliation":[{"name":"University College London  London UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Roy","family":"Homburg","sequence":"additional","affiliation":[{"name":"University College London Hospital NHS Foundation Trust  London UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elizabeth","family":"Timlick","sequence":"additional","affiliation":[{"name":"Homerton Healthcare NHS Foundation Trust  London UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sheetal","family":"Barhate","sequence":"additional","affiliation":[{"name":"Barts Health NHS Trust  London UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kristina","family":"Sackett","sequence":"additional","affiliation":[{"name":"Fertility Plus  London UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Priya","family":"Bhide","sequence":"additional","affiliation":[{"name":"Women's Health Research Unit Wolfson Institute of Population Health, Queen Mary University of London  London UK"},{"name":"Homerton Healthcare NHS Foundation Trust  London UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2025,4,21]]},"reference":[{"key":"e_1_2_10_2_1","volume-title":"Evidence\u2010Based Guideline: Unexplained Infertility","author":"The Unexplained Infertility Guideline Group RD","year":"2023"},{"key":"e_1_2_10_3_1","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/deh870"},{"key":"e_1_2_10_4_1","volume-title":"Fertility: Assessment and Treatment for People With Fertility Problems","author":"NICE","year":"2013"},{"key":"e_1_2_10_5_1","doi-asserted-by":"publisher","DOI":"10.1007\/s10815-022-02689-5"},{"key":"e_1_2_10_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.fertnstert.2022.12.035"},{"key":"e_1_2_10_7_1","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.c332"},{"key":"e_1_2_10_8_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.fertnstert.2017.06.005"},{"key":"e_1_2_10_9_1","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/deaa241"},{"key":"e_1_2_10_10_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140\u20106736(17)32406\u20106"},{"key":"e_1_2_10_11_1","volume-title":"Stata 17","author":"StataCorp","year":"2021"},{"key":"e_1_2_10_12_1","volume-title":"IBM SPSS Statistics for Windows","author":"IBM","year":"2021"},{"key":"e_1_2_10_13_1","doi-asserted-by":"publisher","DOI":"10.3389\/fendo.2021.768975"},{"key":"e_1_2_10_14_1","doi-asserted-by":"publisher","DOI":"10.1177\/1933719117691145"},{"key":"e_1_2_10_15_1","doi-asserted-by":"publisher","DOI":"10.1093\/molehr\/gaad022"},{"key":"e_1_2_10_16_1","doi-asserted-by":"publisher","DOI":"10.1530\/REP-13-0582"},{"key":"e_1_2_10_17_1","doi-asserted-by":"publisher","DOI":"10.3390\/ijms222011278"},{"key":"e_1_2_10_18_1","doi-asserted-by":"publisher","DOI":"10.1055\/s\u20100029\u20101242988"},{"key":"e_1_2_10_19_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.fertnstert.2016.11.029"},{"key":"e_1_2_10_20_1","doi-asserted-by":"publisher","DOI":"10.1111\/1471\u20100528.17451"},{"key":"e_1_2_10_21_1","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.l6802"},{"key":"e_1_2_10_22_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.fertnstert.2020.06.016"}],"container-title":["BJOG: An International Journal of Obstetrics &amp; Gynaecology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/obgyn.onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/1471-0528.18171","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,7,17]],"date-time":"2025-07-17T12:40:55Z","timestamp":1752756055000},"score":1,"resource":{"primary":{"URL":"https:\/\/obgyn.onlinelibrary.wiley.com\/doi\/10.1111\/1471-0528.18171"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,4,21]]},"references-count":21,"journal-issue":{"issue":"9","published-print":{"date-parts":[[2025,8]]}},"alternative-id":["10.1111\/1471-0528.18171"],"URL":"https:\/\/doi.org\/10.1111\/1471-0528.18171","archive":["Portico"],"relation":{},"ISSN":["1470-0328","1471-0528"],"issn-type":[{"value":"1470-0328","type":"print"},{"value":"1471-0528","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,4,21]]},"assertion":[{"value":"2024-10-15","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-03-25","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-04-21","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}