{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T07:01:52Z","timestamp":1771484512551,"version":"3.50.1"},"reference-count":0,"publisher":"The Korean Society for Reproductive Medicine","content-domain":{"domain":["ecerm.org"],"crossmark-restriction":true},"short-container-title":["Clin Exp Reprod Med"],"abstract":"<jats:p>Objective: Letrozole (LE) is the first-line therapy for ovulation induction in polycystic ovary syndrome (PCOS). However, in women who are resistant to standard LE therapy, alternative ovulation induction regimens require further exploration. This study evaluated the efficacy of a novel protocol for stepwise extended LE treatment in patients with anovulatory PCOS undergoing intrauterine insemination who were resistant to the standard dose of 5 mg LE.Methods: The study included 319 women diagnosed with PCOS. LE treatment was administered in a stepwise manner, starting with 5 mg for 5 days (standard group), followed by an extension for another 2 to 5 days (total 7\u201310 days; extended group; LE 5 mg), and subsequently escalating the dose to 7.5 mg for 2\u20135 days (total 12\u201315 days; non-responder extended group; LE 7.5 mg) within a single cycle. Clinical outcomes included ovulation rate and clinical pregnancy rate (CPR).Results: Overall, 219 patients responded to standard LE with follicular development, 83 responded to extended LE 5 mg therapy, and 11 responded to extended LE 7.5 mg. CPRs at 10 weeks of gestation were 18.72% in the standard group, 14.45% in the extended LE 5 mg group, and 11.76% in the non-responder extended LE 7.5 mg group, with no statistically significant differences among them. Multiple pregnancies were observed only in the standard group.Conclusion: The stepwise extended LE regimen appears to be a feasible option for LE-resistant PCOS; however, its efficacy must be further explored and validated in prospective randomized studies.<\/jats:p>","DOI":"10.5653\/cerm.2025.08480","type":"journal-article","created":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T06:00:27Z","timestamp":1771480827000},"update-policy":"https:\/\/doi.org\/10.5653\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Efficacy of stepwise extended letrozole treatment in patients with resistant polycystic ovary syndrome undergoing intrauterine insemination: A 7-year retrospective cohort study"],"prefix":"10.5653","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-5392-7114","authenticated-orcid":true,"given":"Vyjayanthi","family":"Srinivasan","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"3624","published-online":{"date-parts":[[2026,2,19]]},"container-title":["Clinical and Experimental Reproductive Medicine"],"original-title":[],"language":"en","link":[{"URL":"http:\/\/ecerm.org\/upload\/pdf\/cerm-2025-08480.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T06:00:28Z","timestamp":1771480828000},"score":1,"resource":{"primary":{"URL":"http:\/\/ecerm.org\/journal\/view.php?doi=10.5653\/cerm.2025.08480"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,19]]},"references-count":0,"URL":"https:\/\/doi.org\/10.5653\/cerm.2025.08480","relation":{},"ISSN":["2233-8233","2233-8241"],"issn-type":[{"value":"2233-8233","type":"print"},{"value":"2233-8241","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,19]]},"assertion":[{"value":"2025-07-30","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-11-20","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-02-19","order":2,"name":"published","label":"Published online","group":{"name":"publication_history","label":"Publication History"}}]}}