Effect of treatment assignment on intravaginal cleansing in a randomized study of the diaphragm with candidate...

Intravaginal cleansing may predispose women to adverse health outcomes and may interfere with the effectiveness and safety of female-initiated methods for preventing sexually transmitted infections (STIs). In a 4-week randomized study of 192 Malagasy sex workers, we evaluated associations between self-reported intravaginal cleansing and randomization assignment: diaphragm with viscous candidate microbicide gel (Acidform™, TOPCAD, Chicago, IL, licensed to Instead, Coppell, TX), diaphragm with placebo hydroxyethylcellulose gel (HEC, ReProtect LLC, Baltimore, MD), Acidform alone, or HEC alone.

Women were counseled to avoid intravaginal cleansing and were blinded to gel assignment. We evaluated changes in self-reported intravaginal cleansing across the study and assessed the effects of treatment assignment and covariates on frequent (more than once daily) intravaginal cleansing. Significant predictors in domain-specific models were evaluated in an all-domain multiple regression model.

The proportion of women reporting intravaginal cleansing decreased from baseline (97%) to week 1 (82%) (p < 0.001). Self-reported frequent intravaginal cleansing decreased from baseline (87% to 56%) during the same time period (p < 0.001). In adjusted analyses, the Acidform-diaphragm group had 60% lower odds of frequent intravaginal cleansing during the study (odds ratio [OR] 0.4, 95% confidence interval [CI] 0.2-0.8) compared to the control group (HEC only). HEC-diaphragm and Acidform only users did not differ from controls. Living on the coast of Madagascar, not cohabiting, frequent intravaginal cleansing at enrollment, and high coital frequency predicted frequent intravaginal cleansing during follow-up.

Gel characteristics and the diaphragm's presence likely influenced women's cleansing. Viscous gel delivered by a cervical barrier (such as a diaphragm) may minimize the likelihood of frequent intravaginal cleansing.