en Reproductive Biology Original Article Original Article <div style="text-align: justify;"><span style="font-size:14px;"><span style="font-family:Times New Roman;"><b><span lang="TR">Background:</span></b><span lang="TR"> In vitro fertilization (IVF) outcomes are shaped by individual factors, laboratory conditions, and clinician performance; however, while embryologists and laboratory conditions are well studied, clinician-related variables remain less explored.</span><br> <b><span lang="TR">Objective:</span></b><span lang="TR"> This study aims to evaluate whether pregnancy outcomes vary in IVF cycles managed by different clinicians.</span><br> <b><span lang="TR">Materials and Methods: </span></b><span lang="TR">In this cohort study, data of 3017 women who underwent intracytoplasmic sperm injection at the IVF Center of Kadık&ouml;y Florence Nightingale hospital, İstanbul, T&uuml;rkiye from January 2013-December 2020 were extracted from their medical records and retrospectively reviewed. Clinical pregnancy rates were compared between clinicians. </span><br> <b><span lang="TR">Results: </span></b><span lang="TR">Clinical pregnancy rates differed significantly between clinicians, ranging from 13.6-56.0% (p = 0.023). The overall pregnancy rate was 29.9%. In the multivariate analysis, even after adjusting for maternal age, body mass index, duration of infertility, and anti-M&uuml;llerian hormone levels, the clinician variable retained its significance as an independent predictor (adjusted odds ratios: 0.45-2.12, p = 0.018).</span><br> <b><span lang="TR">Conclusion: </span></b><span lang="TR">Our study shows that clinician-related factors independently shape IVF success. Clinical expertise, judgment, and surgical skills affect outcomes throughout the IVF cycle, not only at embryo transfer. Improving laboratory conditions alone is insufficient; clinician training, performance standardization, and ongoing professional development are also essential. Thus, clinician performance should be integrated into quality assurance and further evaluated in prospective multicenter studies.</span><span lang="AR-SA" dir="RTL" style="font-family:"Times New Roman",serif"></span></span></span><br> &nbsp;</div> In vitro fertilization, Clinician performance, Pregnancy rate, Infertility treatment, Embryo transfer. 287 296 http://ijrm.ir/browse.php?a_code=A-10-2842-1&slc_lang=en&sid=1 Oya Korkmaz oya.korkmaz@ozal.edu.tr 0000-0003-2923-5869 No Department of Histology and Embryology, Faculty of Medicine, Malatya Turgut Özal University, Malatya, Türkiye. Seda Karabulut sedakarabulut@medipol.edu.tr 0000-0003-3302-5004 Yes Department of Histology and Embryology, International Faculty of Medicine, Istanbul Medipol University, Istanbul, Türkiye. Elif Yilmaz elif0802@yahoo.com.tr 0000-0001-9903-8946 No In Vitro Fertilization Center, Istanbul Medical Park Hospital, Istanbul, Türkiye. Nuri Delikara ndelikara@netscape.net 0000-0002-7756-8214 No In Vitro Fertilization Center, Istanbul Kadıköy Florence Nightingale Hospital, Istanbul, Türkiye.