An interventional study of Menstrual Pads and Menstrual Cups in Effects of Menstrual Products on the Vaginal Microbiome, sponsored by Swiss Tropical & Public Health Institute. Recruiting at 3 sites in 3 countries. Open to female participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-04-23.
Sponsored by Swiss Tropical & Public Health Institute · Not applicable, Interventional, and Basic science
A three-period crossover trial will study the effects of short-term use of 3 menstrual products (menstrual pad, tampon, menstrual cup) on the bacterial composition of the vaginal microbiome in three countries (Peru, Cameroon, and Switzerland). Each crossover period consists of two menstrual cycles, thus resulting in a 6-month trial. Participants will be randomly assigned to one of 6 exposure sequences (different order of products per sequence); in each sequence, participants will adopt each menstrual product for 2 menstrual cycles. Participants will provide vaginal microbiome samples via self-sample swabs at 3 points during each menstrual cycle. Given the crossover design of the study, there is not a dedicated control group.
In three countries, the investigators will follow a randomized crossover design to study the effects of menstrual products on the vaginal microbiome composition and diversity. Eligible participants who are willing to adopt pads, tampons and menstrual cups to manage their menstruation, and for which baseline composition of their vaginal microbiomes is determined through DNA sequencing of the 16s rRNA gene will enter a three-period crossover trial. Each period of the trial will consist of two menstrual cycles, thus resulting in a 6-month trial. Participants will be randomly assigned to one of six different exposure sequences of menstrual products, as follows:
i) Tampon, Cup, Pad ii) Tampon, Pad, Cup iii) Cup, Tampon, Pad iv) Cup, Pad, Tampon v) Pad, Tampon, Cup vi) Pad, Cup, Tampon
In group "i)", participants will adopt tampons during the first two menstrual cycles (first period of the trial), followed by the adoption of cups during the next two menstrual cycles (second period), and lastly menstrual pads for the next two menstrual cycles (third crossover period). In groups ii) to vi) following the same design but in different sequences. Self-sampling kits will be provided during six consecutive menstrual cycles, a few days before the start of menses. Each kit will contain swabs for three self-sampling points during the menstrual cycle and the corresponding menstrual products.
Swiss Tropical & Public Health Institute is the lead sponsor of 58 studies on the registry; 9 are open to participants now.
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Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will adopt tampons during the first two menstrual cycles (first period of the trial), followed by adoption of cups during the next two menstrual cycles (second period), and lastly menstrual pads for the next two menstrual cycles (third crossover period).
Other: Menstrual Pads · Other: Menstrual Cups · Other: Tampons
Participants will adopt tampons during the first two menstrual cycles (first period of the trial), followed by adoption of pads during the next two menstrual cycles (second period), and lastly menstrual cups for the next two menstrual cycles (third crossover period).
Other: Menstrual Pads · Other: Menstrual Cups · Other: Tampons
Participants will adopt menstrual cups during the first two menstrual cycles (first period of the trial), followed by adoption of tampons during the next two menstrual cycles (second period), and lastly menstrual pads for the next two menstrual cycles (third crossover period).
Other: Menstrual Pads · Other: Menstrual Cups · Other: Tampons
Participants will adopt menstrual cups during the first two menstrual cycles (first period of the trial), followed by adoption of menstrual pads during the next two menstrual cycles (second period), and lastly tampons for the next two menstrual cycles (third crossover period).
Other: Menstrual Pads · Other: Menstrual Cups · Other: Tampons
Participants will adopt menstrual pads during the first two menstrual cycles (first period of the trial), followed by adoption of tampons during the next two menstrual cycles (second period), and lastly menstrual cups for the next two menstrual cycles (third crossover period).
Other: Menstrual Pads · Other: Menstrual Cups · Other: Tampons
Participants will adopt menstrual pads during the first two menstrual cycles (first period of the trial), followed by adoption of menstrual cups during the next two menstrual cycles (second period), and lastly tampons for the next two menstrual cycles (third crossover period).
Other: Menstrual Pads · Other: Menstrual Cups · Other: Tampons
Participants adopt menstrual pads to manage their menstruation during 2 menstrual cycles. For each menstrual cycle, participants will provide vaginal microbiome samples via self-sampled swabs at 3 points.
Participants adopt menstrual cups to manage their menstruation during 2 menstrual cycles. For each menstrual cycle, participants will provide vaginal microbiome samples via self-sampled swabs at 3 points.
Participants adopt tampons to manage their menstruation during 2 menstrual cycles. For each menstrual cycle, participants will provide vaginal microbiome samples via self-sampled swabs at 3 points.
Log-ratio of Dialister to Lactobacillus crispatus relative abundances in vaginal swabs (continuous variable)
The abundances of each bacterial taxa are estimated from the DNA amplification and sequencing of amplicons from the 16S rRNA gene.
Time frame: Monthly, after menstruation ends, through study completion, an average of 6 months.
Log-ratio of Bifidobacterium vaginalis to Lactobacillus relative abundances in vaginal swabs (continuous variable)
The abundances of each bacterial taxa are estimated from the DNA amplification and sequencing of amplicons from the 16S rRNA gene.
Time frame: Monthly, after menstruation ends, through study completion, an average of 6 months.
Log-ratio of Prevotella to Lactobacillus relative abundances in vaginal swabs (continuous variable)
The abundances of each bacterial taxa are estimated from the DNA amplification and sequencing of amplicons from the 16S rRNA gene.
Time frame: Monthly, after menstruation ends, through study completion, an average of 6 months.
Dominant taxon in vaginal swabs (categorical variable)
The dominant taxon in a vaginal swab is defined as the most abundant taxon found with a relative abundance of at least 30% of the total bacterial DNA sequences found in the sample.
Time frame: Monthly, after menstruation ends, through study completion, an average of 6 months.
Community state type in vaginal swabs (categorical variable)
The community state type in a vaginal swab is defined using the VALENCIA algorithm as described in this article: France, M.T., Ma, B., Gajer, P. et al. VALENCIA: a nearest centroid classification method for vaginal microbial communities based on composition. Microbiome 8, 166 (2020). https://doi.org/10.1186/s40168-020-00934-6
Time frame: Monthly, after menstruation ends, through study completion, an average of 6 months.
Total bacterial load in vaginal swabs (continuous variable)
Indirectly estimated with qPCR of the 16S rRNA gene
Time frame: Monthly, after menstruation ends, through study completion, an average of 6 months.
Self-reported vaginal complaints (discrete variable)
Self-reported through follow up surveys along the six-month trial
Time frame: Monthly, from enrollment until study completion, an average of 6 months.
Vaginal pH (ordinal variable)
Measured with a vaginal swab and a fixed indicator (3.6 - 6.1), just after menstruation ends.
Time frame: Monthly, after menstruation ends, through study completion, an average of 6 months.
Alpha diversity (continuous variable)
Alpha diversity indices (e.g., Shannon, Simpson) are estimated for each vaginal swab sample to quantify microbial richness and evenness.
Time frame: Monthly, after menstruation ends, through study completion, an average of 6 months.
Log-ratio of Gardnerella module to L. crispatus module relative abundances (continuous variable)
The abundances of each bacterial module are estimated from the DNA amplification and sequencing of amplicons from the 16S rRNA gene.
Time frame: Monthly, after menstruation ends, through study completion, an average of 6 months.
Log-ratio of Prevotella module to L. crispatus module relative abundances (continuous variable)
The abundances of each bacterial module are estimated from the DNA amplification and sequencing of amplicons from the 16S rRNA gene.
Time frame: Monthly, after menstruation ends, through study completion, an average of 6 months.
molBV score (discrete variable)
The molBV score in a vaginal swab is defined and derived as described in this article: Usyk, M., Schlecht, N.F., Pickering, S. et al. molBV reveals immune landscape of bacterial vaginosis and predicts human papillomavirus infection natural history. Nat Commun 13, 233 (2022). https://doi.org/10.1038/s41467-021-27628-3.
Time frame: Monthly, after menstruation ends, through study completion, an average of 6 months.
Plan to share: No
Started Apr 2026 (actual). Primary completion is estimated for Dec 2026, 8 months after the start.
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