{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,9]],"date-time":"2026-04-09T16:55:24Z","timestamp":1775753724929,"version":"3.50.1"},"reference-count":22,"publisher":"S. Karger AG","issue":"2","license":[{"start":{"date-parts":[[2025,6,18]],"date-time":"2025-06-18T00:00:00Z","timestamp":1750204800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/karger.com\/pages\/terms-and-conditions"},{"start":{"date-parts":[[2025,6,18]],"date-time":"2025-06-18T00:00:00Z","timestamp":1750204800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/karger.com\/pages\/terms-and-conditions"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gynecol Obstet Invest"],"abstract":"<jats:p>Objectives: Address and identify the sub-group of patients that might benefit from letrozole co-treatment throughout the entire ovarian stimulation (OS). Design: A retrospective cohort study. Patients: Patients who underwent two successive IVF cycle attempts, where the 2nd included the co-administration of 5 mg Letrozole from OS day 1 until trigger day. Setting: IVF institute of a tertiary medical center. Methods: First and second cycle attemtps were compared with regard to cycle characteristics and results. Different subroups according to ovarian response were considered. Results: Two hundred patients met the inclusion criteria and were included in the study. Of whom, 65 were poor responders (oocytes \u22643) during the first IVF cycle attempt, 85 were sub-optimal responders (4\u20139 oocytes), and 50 were normal responders (\u226510 oocytes). The total dose of gonadotropins (4,525 \u00b1 1,553 vs. 4,293 \u00b1 2,166, p = NS) and length of stimulation (11.3 \u00b1 2.2 vs. 11.1 \u00b1 2.3, p = NS) were comparable between the two cycle attempts. Numbers of follicles \u226513 mm (7.2 \u00b1 4.7 vs. 6.2 \u00b1 4.3, p &lt; 0.001), retrieved oocytes (8.6 \u00b1 6.1 vs. 6.9 \u00b1 5.5, p &lt; 0.001), zygotes (5.7 \u00b1 4.5 vs. 4.5 \u00b1 3.7, p &lt; 0.001) and number of top quality embryos (TQE) (2.5 \u00b1 2.5 vs. 1.8 \u00b1 1.9, p &lt; 0.001) were significantly higher in letrozole cycles. Sub-analysis according to patients\u2019 ovarian response during the first attempt revealed that the poor and sub-optimal responders significantly benefit from the letrozole co-administration, while the normal responders did not. Conclusions: Letrozole co-administration during OS for IVF increases the number of retrieved oocytes, zygotes, and TQE in poor and sub-optimal responders but not in normal responders.<\/jats:p>","DOI":"10.1159\/000546147","type":"journal-article","created":{"date-parts":[[2025,6,19]],"date-time":"2025-06-19T12:00:51Z","timestamp":1750334451000},"page":"220-225","source":"Crossref","is-referenced-by-count":0,"title":["Does Daily Co-Administration of Gonadotropins and Letrozole during the Ovarian Stimulation Improve IVF Outcome for Normal, Poor, and Sub-Optimal Responders?"],"prefix":"10.1159","volume":"91","author":[{"given":"Jigal","family":"Haas","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Raoul","family":"Orvieto","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Adva","family":"Aizer","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ettie","family":"Maman","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Merav","family":"Noach-Hirsh","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lilach","family":"Marom Haham","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Oshrit","family":"Lebovitz","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Moran","family":"Shapira","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ravit","family":"Nahum","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"127","published-online":{"date-parts":[[2025,6,18]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","DOI":"10.1210\/jcem.84.8.5929"},{"key":"ref2","doi-asserted-by":"publisher","DOI":"10.1210\/endo-109-4-1303"},{"key":"ref3","doi-asserted-by":"publisher","DOI":"10.1210\/endo-119-3-1403"},{"key":"ref4","doi-asserted-by":"publisher","DOI":"10.1172\/JCI2081"},{"key":"ref5","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/den428"},{"key":"ref6","doi-asserted-by":"publisher","DOI":"10.1016\/j.fertnstert.2005.01.117"},{"key":"ref7","doi-asserted-by":"publisher","DOI":"10.1093\/humupd\/dmr051"},{"key":"ref8","doi-asserted-by":"publisher","DOI":"10.1016\/j.ajog.2022.03.051"},{"key":"ref9","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/deac145"},{"key":"ref10","doi-asserted-by":"publisher","DOI":"10.1080\/09513590.2016.1177013"},{"key":"ref11","doi-asserted-by":"publisher","DOI":"10.1186\/s12958-017-0288-8"},{"key":"ref12","doi-asserted-by":"publisher","DOI":"10.1186\/s13048-020-00666-z"},{"key":"ref13","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/dev316"},{"key":"ref14","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/dem221"},{"key":"ref15","doi-asserted-by":"publisher","DOI":"10.3389\/fendo.2021.676133"},{"key":"ref16","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa1313517"},{"key":"ref17","doi-asserted-by":"publisher","DOI":"10.1007\/s10815-020-02030-y"},{"key":"ref18","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2007.14.8700"},{"key":"ref19","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/deac119"},{"key":"ref20","doi-asserted-by":"publisher","DOI":"10.1016\/j.ejogrb.2016.05.027"},{"key":"ref21","doi-asserted-by":"publisher","DOI":"10.5468\/ogs.2014.57.3.216"},{"key":"ref22","doi-asserted-by":"publisher","DOI":"10.18502\/ijrm.v17i9.5101"}],"container-title":["Gynecologic and Obstetric Investigation"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/karger.com\/article-pdf\/doi\/10.1159\/000546147","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/karger.com\/article-pdf\/doi\/10.1159\/000546147","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,9]],"date-time":"2026-04-09T16:01:06Z","timestamp":1775750466000},"score":1,"resource":{"primary":{"URL":"https:\/\/karger.com\/article\/doi\/10.1159\/000546147"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,6,18]]},"references-count":22,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026,4,9]]},"published-print":{"date-parts":[[2026,4,8]]}},"URL":"https:\/\/doi.org\/10.1159\/000546147","archive":["Portico"],"relation":{},"ISSN":["0378-7346","1423-002X"],"issn-type":[{"value":"0378-7346","type":"print"},{"value":"1423-002X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,6,18]]}}}