Effects of Menstrual Products on the Vaginal MicrobiomeIMVAHANCT06646185
Improving Menstrual and VAginal Health for All
A study testing Menstrual Pads, Menstrual Cups and Tampons in people with Effects of Menstrual Products on the Vaginal Microbiome, run by Swiss Tropical & Public Health Institute at 3 sites in 3 countries.
Trial summary
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). Read more about this study
- Who is it for?
- Ages 18 to 35 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Effects of Menstrual Products on the Vaginal Microbiome
- What is being tested?
- Menstrual Pads, Menstrual Cups and Tampons
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 3 sitesin 3 countries
- Study dates
- 15 Apr 2026to 31 Dec 2026
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 35 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- able to provide informed consent;
- aged 18-35;
- residing in the recruitment region and expecting to reside in the same region for at least six months following recruitment (Yaoundé/ Gounougou, Cameroon; Loreto/Lima/Maynas provinces, Peru; or Basel-Landschaft and Basel-Stadt cantons, Switzerland);
- are native speakers or are able to read and understand one of the following languages in each respective country (German, French, Italian, English or Spanish in Switzerland; French or English in Cameroon; Spanish in Peru);
- had menstrual cycles of 21-35 days for at least the last 4 months;
- had menses which lasted at least 3 days for at least the last 4 months.
Who cannot join
- experienced a menstrual abnormality with any of the menstrual cycles in the last 4 months (such as oligomenorrhea or amenorrhea, or bleed more than 7 days a month);
- are pregnant or actively trying to become pregnant;
- are breastfeeding;
- used antibiotics and/or vaginal antifungals in the last 30 days prior to recruitment;
- had a vaginal birth in the last 6 months;
- vaginal surgery, perineal surgery, uterine surgery, miscarriage or abortion in the last 6 months;
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- history of Toxic Shock Syndrome ;
- positive to detection of the toxic shock syndrome toxin-1 gen (tst) using Polymerase Chain Reaction (PCR);
- Intrauterine device in situ;
- under medication (treatment against infectious or chronic disease) at the time of recruitment or during the 3 weeks prior to recruitment;
- clinical symptoms of vaginal infection;
- smoker.
Trial locations and contacts
3 sites in 3 countries. Contact the study team or a site near you to ask about taking part.
3 sites in 3 countries
Cameroon1 site, 1 recruiting
- Recruiting
Centre de Recherche sur les Maladies Emergentes et Re-Emergentes
Yaoundé, Yaoundé, 3
Esemu Livo, PhD, +237 674 632 078, esemu_livo@yahoo.com
Marie Josiane Kenfack, PhD(c), +237676783165, kenfackjosiane@yahoo.fr
Peru1 site, 1 recruiting
- Recruiting
Universidad Nacional de la Amazonia Peruana
Iquitos, Iquitos, 16007
Viviana Pinedo, PhD, +51 955 850 853, viviana.pinedo@unapiquitos.edu.pe
Sandra Condori, PhD, +32 488 15 54 52, sandra.condori@uantwerpen.be
Switzerland1 site, 1 recruiting
- Recruiting
Swiss Tropical and Public Health Institute
Allschwil, Allschwil, 4123
Sonja Merten, MD MPH PhD, +41 79 640 17 27, sonja.merten@swisstph.ch
Monica Ticlla, PhD, monicaroxana.ticllaccenhua@unibas.ch
About this study
Official title: IMVAHA: Improving Menstrual and VAginal Health for All
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.
Read the detailed description
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:
- 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.
- Being tested
- Menstrual Pads, Menstrual Cups, Tampons
- Keywords
- vaginal microbiome, menstruation, crossover study, menstrual products
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Menstrual PadsOther
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.
Menstrual CupsOther
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.
TamponsOther
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.
| Study group | Role | What they receive |
|---|---|---|
| TamponCupPad | Other | 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). Receives: Other: Menstrual Pads; Other: Menstrual Cups; Other: Tampons |
| TamponPadCup | Other | 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). Receives: Other: Menstrual Pads; Other: Menstrual Cups; Other: Tampons |
| CupTamponPad | Other | 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). Receives: Other: Menstrual Pads; Other: Menstrual Cups; Other: Tampons |
| CupPadTampon | Other | 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). Receives: Other: Menstrual Pads; Other: Menstrual Cups; Other: Tampons |
| PadTamponCup | Other | 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). Receives: Other: Menstrual Pads; Other: Menstrual Cups; Other: Tampons |
| PadCupTampon | Other | 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). Receives: Other: Menstrual Pads; Other: Menstrual Cups; Other: Tampons |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: Monthly, after menstruation ends, through study completion, an average of 6 months.
Secondary outcomes (11)
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.
Measured: 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.
Measured: 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.
Measured: 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
Measured: 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
Measured: 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
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: Monthly, after menstruation ends, through study completion, an average of 6 months.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Oct 2024
- Study start15 Apr 2026
- Primary completion31 Dec 2026 (estimated)
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Effects of Menstrual Products on the Vaginal MicrobiomeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- 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. No wash-out period is included because participants can not stop the use of menstrual products to manage their menstruation.
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Swiss Tropical & Public Health Institute
- Sponsor type
- University, hospital or other
- Collaborators
- Universidad Nacional de la Amazonia Peruana, Universidad Peruana Cayetano Heredia, Centre de Recherche sur les Maladies Emergentes et Re-Emergentes, Universiteit Antwerpen
- Responsible party
- Principal investigator, Sonja Merten, Swiss Tropical & Public Health Institute
- Investigators
- Sonja Merten, PhD, Principal investigator, Swiss Tropical & Public Health Institute
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06646185
- Sponsor's protocol ID
- 2023-30
- Acronym
- IMVAHA
- Status last verified
- Apr 2026
- First submitted
- 24 Sep 2024
- Last updated
- 23 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Ticlla MR, Dumbaugh M, Condori-Catachura S, Kenfack J, Hattendorf J, Van Der Donck L, Arista KM, Arora N, Gebert S, Ackermann L, Ahannach S, Riveros M, Blas MM, Kenmoe S, Barriere FY, Shea AA, Pinedo-Cancino V, Rivas-Ruiz R, Di Cecco V, Esemu L, Ochoa TJ, Lebeer S, Martin Hilber A, Merten S. Improving menstrual and vaginal health for all (IMVAHA): protocol for a randomised cross-over trial assessing the impact of menstrual products on the vaginal microbiome of women aged 18-35 years in Cameroon, Peru and Switzerland. BMJ Open. 2026 Apr 22;16(4):e108568. doi: 10.1136/bmjopen-2025-108568.
PubMed 42020126