Caspian Journal of Reproductive Medicine

en Maternal and paternal predictors of pregnancy outcomes following intrauterine insemination: A retrospective cohort analysis Reproductive Health Reproductive Health پژوهشي Original Research <div style="text-align: justify;">Background: Intrauterine insemination (IUI) is a commonly used first‑line fertility treatment, yet pregnancy rates vary widely, and the relative influence of maternal and paternal factors remains unclear. Few studies have evaluated these determinants simultaneously, creating a gap in evidence for optimizing patient selection. This study examined key maternal and semen‑related predictors of IUI success. Methods: This retrospective descriptive‑analytical study included 211 infertile couples undergoing 335 IUI cycles at an academic infertility center between 2017 and 2018. Eligible couples had ≥1 year of infertility, normal semen thresholds (motility ≥20%, total count ≥4 million, morphology ≥4%), no severe systemic disease, and complete follow‑up. Maternal variables included age, body mass index (BMI), endometrial thickness, follicle size, and number of mature follicles. Paternal variables included sperm count, progressive motility, and morphology. Pregnancy outcomes were assessed using β‑hCG testing and confirmed by ultrasound. Associations were examined using standard comparative analyses. Results: The pregnancy rate was 20.4% per couple and 12.8% per cycle. Endometrial thickness was significantly greater in successful cycles (8.3 ± 0.9 mm) compared with unsuccessful cycles (7.4 ± 1.7 mm; p = 0.002). Shorter infertility duration (p = 0.007) and fewer IUI attempts (p = 0.037) also predicted success. Maternal age, BMI, sperm count, progressive motility, and morphology showed no significant associations with pregnancy. Conclusion: Endometrial thickness was the strongest predictor of IUI success, with optimal outcomes observed at 7–9 mm. Infertility duration and number of IUI attempts also influenced pregnancy likelihood, while semen parameters and most maternal characteristics did not. These findings highlight the importance of uterine receptivity and timely intervention. Further multicenter studies with additional biomarkers are recommended to enhance predictive models and guide individualized fertility care.</div> Endometrial thickness, Fertility factors, Infertility outcomes, Intrauterine insemination semen analysis 13 19 http://caspjrm.ir/browse.php?a_code=A-12-173-3&slc_lang=en&sid=1 Ramesh Baradaran Bagheri 10031947532846002638 10031947532846002638 No Atusa Karimi 10031947532846002639 10031947532846002639 Yes Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran Zahra Sehat 10031947532846002640 10031947532846002640 No Mohammad Ali Rezaei mohammadrezaei362@gmail.com 10031947532846002641 10031947532846002641 No Alborz University of Medical Sciences, Karaj, Iran Naser Amrijanati 10031947532846002642 10031947532846002642 No