Abstract / Summary
Purpose: To examine the association between inseminated progressive motile sperm count (IPMSC) and pregnancy test positivity after intrauterine insemination (IUI), and to identify a useful threshold.Materials and methods: This retrospective cohort study included 564 IUI cycles in 364 women treated between January 2025 and July 2026. Semen samples were prepared by density-gradient centrifugation followed by swim-up, and 0.5 mL was inseminated. IPMSC was calculated from post-wash concentration and insemination volume. IPMSC was analysed categorically and continuously and compared with pre-wash counts. Associations were assessed using generalized estimating equations, with patient identity as the clustering variable.Results: Pregnancy test positivity was 12.2% per cycle and 19.0% per woman. Pre-wash sperm parameters did not differ between positive and negative cycles. Median IPMSC was higher in positive cycles (15.0 vs 10.0×10⁶, p=0.012). One of 76 cycles with an IPMSC below 2×10⁶ had a positive test (1.3%), compared with 13.9% at or above this level (p