ABSTRACT Background and Aims Male infertility, often characterized by impaired sperm parameters, remains a significant clinical challenge. This study aimed to evaluate the efficacy and safety of hirudotherapy (medicinal leech therapy) in improving sperm quality parameters in men with idiopathic infertility. Methods In this randomized controlled trial, 50 male volunteers aged 20–50 years were randomly assigned to either an experimental group receiving weekly leech therapy for 3 months (n = 25) or a control group receiving no intervention (n = 25). Semen parameters were assessed at baseline and after the intervention period. Evaluations included semen analysis according to WHO guidelines, sperm DNA fragmentation by TUNEL assay, protamine deficiency by chromomycin A3 staining, and assessments of sperm viability and morphology using flow cytometry and Diff‐Quik staining. Statistical analyses were performed using SPSS version 21.0, with significance set at p < 0.05. Results Compared to the control group, leech therapy significantly improved several sperm quality parameters. Sperm concentration increased from 57.7 ± 17.1 to 63.4 ± 13.1 million/mL (p = 0.006). Total sperm count, progressive motility, and normal morphology also improved significantly (p < 0.05). DNA fragmentation decreased significantly in the experimental group compared to controls (mean difference: −3.9%; p = 0.04). Protamine deficiency also showed a significant reduction (p = 0.02). No adverse effects related to the intervention were observed. Conclusion This randomized controlled trial suggests that hirudotherapy may improve sperm quality parameters, including concentration, motility, morphology, and DNA integrity, in men with idiopathic infertility. These findings support further investigation of leech therapy as a complementary approach to male infertility management. Trial Registration: IRCT20230502058045N.
Abtahi‐Forooshani et al. (Sun,) studied this question.