Evaluation of the levels of secretory leukocyte protease inhibitor in the cervical mucus of women with unexplained infertility

© 2020 Japan Society of Obstetrics and GynecologyAim: Secretory leukocyte protease inhibitor (SLPI) has specific effects on the immune system. SLPI is overexpressed in inflammation triggered by immune responses, which could have significant effects on the local immune responses in cervical mucosa. This over expression may be greater in women with unexplained infertility, which would increase the immune reaction in the cervical region against sperm. The aim of our study was to assess the levels of SLPI in cervical mucus in women with unexplained infertility. Methods: This prospective cross-sectional study was conducted using 50 Caucasian volunteers between 20 and 40 years old. The 50 participants were divided into two groups as unexplained infertility (n = 20) and control (n = 30). The control group comprised healthy fertile women with demographic characteristics similar to those of the infertility group. The enzyme-linked immunosorbent assay method was used to assess SLPI levels in the cervical mucus of all participants. Results: The median SLPI level in cervical mucus was 3767 (3541–4594, 95% CI) pg/mL (25th percentile; 3139 pg/mL, 75th percentile; 5047 pg/mL) in the unexplained-infertility group and 3204 (2602–3539, 95% CI) pg/mL (the 25th percentile = 2615 pg/mL; 75th percentile = 3990 pg/mL) in the control group, which was a significant difference (P = 0.013). Conclusion: Our results indicated that SLPI levels in cervical mucus were remarkably higher in patients with unexplained infertility than in the control group