In this randomized prospective study, we evaluated the effect of receipt of four product combinations on frequent intravaginal cleansing: the diaphragm with candidate microbicide gel (Acidform), the diaphragm with placebo gel (HEC), Acidform alone, and HEC alone. We found that women whose gel was viscous and delivered by a diaphragm (i.e., women in the Acidform-diaphragm group) were most successful in avoiding frequent intravaginal cleansing during the study. Other predictors of frequent cleansing included living in coastal areas of Madagascar (Mahajanga, Toamasina, and Antsiranana), reporting frequent intravaginal cleansing at enrollment, and reporting high coital frequency during the study; cohabiting with a male partner was inversely related to frequent cleansing.
Little has been published about intravaginal practices in Madagascar. A mixed-method study conducted among sex workers in Antananarivo, Toamasina, and Mahajanga revealed that participants generally cleansed intravaginally with their forefinger and water whenever they bathed and between clients.24
A qualitative study conducted at a public clinic in Antananarivo28
found that women considered intravaginal cleansing necessary to remove impurities before and after sex. Additionally, women believed that their male partners would be displeased if they failed to cleanse before sex. In the present study, anecdotal reports from the field revealed that some women found the added moisture from study gels uncomfortable and that some were concerned that men would confuse the gels with ejaculate from previous partners.
We consider it likely that the presence of a diaphragm and the physical characteristics of the gels influenced women's choices about intravaginal cleansing. Gels may have been sensed as moisture or wetness, and vaginal cleansing may have been motivated by the volume of gel that was present; that is, as more gel accumulated in the vagina, women may have experienced a greater compulsion to cleanse despite having been instructed not to do so. In the two diaphragm-gel groups, there would have been comparatively less gel in the vagina, and we would therefore expect less cleansing. Nevertheless, we observed lower levels of cleansing in the Acidform-diaphragm group but not in the HEC-diaphragm group. HEC is less viscous than Acidform, and it may have been more likely to leak around the edges of the diaphragm. Thus, it is possible that women in the HEC-diaphragm group were exposed to more gel on the exterior (noncervix) side of the diaphragm and more often sensed an unacceptable degree of moisture or wetness compared to women in the Acidform-diaphragm group. In summary, women in the Acidform-diaphragm group may have been least likely to reach the point where an unacceptable amount of gel had accumulated, and this may explain why Acidform-diaphragm participants had the lowest odds of frequent intravaginal cleansing during the study.
We considered alternative explanations for our finding that receipt of a diaphragm with Acidform was inversely associated with frequent intravaginal cleansing. These included differential adherence, differential condom use, and differing expectations of product efficacy. As we reported previously,25
the Acidform-diaphragm group reported somewhat higher levels of study product use during sex (compared to the control group of HEC alone). Nevertheless, the results of our sensitivity analysis do not support differential adherence as an explanation for our findings. The sensitivity analysis replicated the final model of intravaginal cleansing but included only weeks of follow-up during which women reported 100% adherence to study regimens. Results were similar to those of the main analysis: when self-reported adherence was optimal, the inverse association between receipt of diaphragm with Acidform and frequent cleansing remained.
The literature suggests an inverse association between condom use and intravaginal cleansing.21,29
Although all groups received equivalent counseling about condom use, we previously reported that self-reported condom use was lowest in the Acidform-diaphragm group (62% of acts vs. the overall average of 66%).25
This would lead us to expect comparatively more cleansing in the Acidform-diaphragm group. Thus, differential condom use is an unlikely explanation for our findings.
If study participants believed that intravaginal cleansing protects women from STI or pregnancy and if expectations of product efficacy varied by study group, this could have caused differences between groups in intravaginal cleansing. It is unlikely that the type of gel received led to differing expectations of efficacy. Participants were blinded to whether they received active or placebo gel. Although some women presumably noticed that their gel was thicker or thinner than the alternative, we have no reason to believe that women knew whether they had received active or placebo gel. Women in diaphragm arms may have felt more protected than women who received a gel alone. Nevertheless, this increased sense of protection would have led to lower levels of cleansing in both diaphragm groups, not just the Acidform-diaphragm group.
As for other predictors of frequent cleansing, coastal and inland regions of Madagascar have different cultural norms surrounding intravaginal cleansing; intravaginal cleansing is more strongly encouraged on the coast. Additionally, coastal areas are less temperate, and the heat and resulting perspiration may increase women's desires to cleanse. Women who cleansed frequently before enrolling in the study may have found it particularly difficult to avoid frequent cleansing during the study. Our finding that women with the highest coital frequency cleansed most frequently is consistent with other research in this population, which found that many women cleanse intravaginally between clients.24
Cohabiting with a husband or other sexual partner may afford less privacy for intravaginal cleansing compared to not sharing living space with a partner.
Limitations of this study include small sample size, relatively short follow-up, reliance on self-reported data, and apparent imbalance on baseline characteristics. Despite the limited statistical power that our small sample size afforded, we identified a significant effect of receiving the diaphragm with Acidform on frequent cleansing. Although we could not evaluate the long-term effect of treatment assignment on cleansing, 4 weeks may have been sufficient for participants to become accustomed to their study products and adapt their intravaginal cleansing habits accordingly. Reliance on self-reported data, which can be subject to recall and social desirability biases, is another limitation. Social desirability is a plausible explanation for the large overall drops in self-reported intravaginal cleansing from enrollment to the first follow-up visit. However, we would not expect differences between groups in either recall or the social desirability of reporting intravaginal cleansing during the study, and, thus, we do not consider our main findings about predictors of frequent cleansing to have been biased by social desirability. Although some may consider baseline differences among treatment groups to be a limitation of the study, we would argue that it is unrealistic to expect balance every time random selection is implemented30
and that we have likely achieved better overall balance than we would have with nonrandom selection.
Strengths of this study include the longitudinal design and, despite some apparent imbalances among treatment groups, randomization of study participants. The longitudinal design allowed us to account for temporality (e.g., by adjusting regression models for change over time). By randomizing participants, we reduced the likelihood of substantial confounding by women's measured or unmeasured baseline characteristics.