Intrauterine insemination (IUI) remains a widely used first-line fertility treatment, yet outcomes vary considerably. This narrative synthesis of studies published between 2000 and 2024 integrates data from randomized trials, cohort studies, and reviews to clarify determinants of success. Maternal age, BMI, psychological stress, and nutritional status—including adequate intake of folate, vitamins B12, A, C, E, and trace elements such as zinc and selenium—significantly influence pregnancy rates.
Female-specific clinical thresholds, particularly endometrial thickness of 6–10 mm and the number of mature follicles under optimized ovarian stimulation (notably gonadotropin-based protocols), are consistently associated with improved outcomes. Male factors, including post-wash total motile sperm count (≥5–10 million), morphology, and DNA fragmentation index, are equally critical. Procedural…
