Objective: To conduct a population-based evaluation of vaginal douching as a risk factor for acute pelvic inflammatory disease (PID), emphasizing timing, frequency, and reasons for douching.
Methods: A population-based case-control study was conducted at Group Health Cooperative of Puget Sound, a staff-model health maintenance organization located in western Washington state. The cases (N = 131) were women 18-40 years of age who experienced a first episode of clinically diagnosed acute PID. Both hospitalized and ambulatory-care patients were identified. Medical records were reviewed for clinical inclusion criteria and for additional evidence of inflammation/infection. Controls (N = 294) were chosen from a population-based series of randomly selected women from a concurrent Group Health study of ectopic pregnancy. Of the women identified, 72.4% of cases and 73.4% of controls agreed to participate.
Results: Relative to women who reported never having douched, women who douched during the previous 3 months had a risk of PID of 2.1 after controlling for other measured risk factors (95% confidence interval [CI] 1.2-3.9). Women who douched at least once a week had a higher estimated risk (odds ratio 3.9, 95% CI 1.4-10.9) than those who douched less often (odds ratio 1.8, 95% CI 1.0-3.4). The risk was highest in the small group of women who gave infection as the reason for douching (odds ratio 7.9, 95% CI 2.6-24.2). However, exclusion of this group did not eliminate the association among the remaining women (odds ratio 3.0, 95% CI 1.0-9.1 for douching at least once a week).
Conclusion: These population-based data lend added support to the hypothesis that vaginal douching can predispose a woman to PID.