Post-coital vaginal douching is risky for non-regression of low-grade squamous intraepithelial lesion of the cervix

Background: Vaginal douching is a common practice worldwide. Its effect on the natural history of the early lesion of human papillomavirus (HPV) infection, low-grade squamous intraepithelial lesion (LSIL), is unknown. Methods: In a prospective nation-wide cohort (n = 1332), epidemiological variables including habit of vaginal douching after intercourse and outcomes of LSIL were studied. Colposcopy-confirmed LSIL women (n = 295) were followed every 3 months. Parameters of HPV infection, sexual behavior, personal hygiene and environmental exposures were compared with the follow-up outcomes. Results: There was a 15% chance of HSIL co-existing with the LSIL cytology result. Eight percent of colposcopy-confirmed LSIL were found with HSIL in 1 year. With a follow-up of up to 36 months, 83% LSIL regressed, 11% progressed and 6% persisted. The mean time (95% CIs) to regression and progression were 5.2 (4.7-5.8) and 8.0 (5.8-10.3) months, respectively. Risk factors of the non-regression of LSIL included HPV prevalence on enrollment, habit of vaginal douching after intercourse with a hygiene product and non-regular Pap screening, with odd ratio of 4.4 (1.9-10.3), 3.14 (1.04-9.49) and 2.12 (1.24-3.62), respectively. HPV prevalence and vaginal douching also conferred a slower regression of LSIL (8.0 vs. 4.1 months, P < .001 and 8.0 vs. 5.6 months, P = 0.02, respectively). Conclusion: The study disclosed a transient but warning nature of cytological LSIL. Practicing of vaginal douching after intercourse, especially with hygiene products, is associated with non-regression of LSIL.