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NCT Number: NCT07199998

Impact of Internal Menstrual Protections on Immunity and Vaginal Microbiota

The availability, effectiveness, and safety of menstrual protection represent a key public health issue. However, research on women's menstrual and sexual health remains extremely limited. Whether societal or pathological, many hypotheses are emerging regarding the effects of menstrual protection products, yet little attention has been given to the products themselves, their societal role, or their physiological and pathological consequences. Internal menstrual products, such as tampons and menstrual cups, are widely used but are subject to limited regulatory oversight, and few studies have investigated their long-term effects on vaginal health.

This study aims to investigate how different types of menstrual protection influence vaginal microbiota, immune responses, and the recurrence of gynecological conditions such as bacterial vaginosis, mycosis, or dysbiosis. Biological samples (vaginal, cervical, urinary, and blood) will be collected to analyze vaginal microbiota composition and local immunity. Participants will be divided into three groups based on their main type of menstrual protection: menstrual cup users, tampon users, and external pad users. The study will compare these groups to assess potential differences in vaginal health and immune response related to menstrual product use.

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Key information

About this study

The aim of this study is to investigate potential links between the type of menstrual protection used and variations in vaginal health, including microbial composition, immune responses, and exposure to environmental pollutants.

The project consists of two complementary components:

  • Epidemiological Study: An online survey will be conducted with 1,500 to 1,800 participants, collecting detailed information on the usage habits of menstrual protection products (such as menstrual cups, tampons, and external pads), as well as self-reported symptoms and history of urogenital infections. This dataset will allow for large-scale correlation analyses between menstrual hygiene practices and women's health indicators.
  • Clinical Study:

A total of approximately 300 women will be recruited and divided into three groups based on their primary menstrual protection method:

Group 1: Menstrual cup users Group 2: Tampon users Group 3: External sanitary pad users

All clinical participants will undergo a gynecological examination and provide vaginal, cervical, urinary, and blood samples. These biological samples will be used for in-depth analysis across three main areas:

  • Microbiology: studying the vaginal microbiota composition and identifying infectious or dysbiotic profiles.
  • Immunology: assessing local immune responses, including cytokine levels and antibody titers.
  • Toxicology: measuring exposure to potential environmental pollutants through menstrual product use.

Sequencing, immune profiling, pollutant quantification, and cytobacteriological screening will be conducted to evaluate potential differences between groups. These analyses aim to provide a better understanding of how menstrual protection methods may influence vaginal ecosystem balance, immune activity, and overall urogenital health.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Willingness to comply with all study procedures and availability for the duration of the study.
  • Female, aged 18 to 49 years.
  • In general good health, as determined by medical history.
  • Covered by the national health insurance system.
  • Willing to sign a written informed consent form.
  • Has already experienced menstruation prior to the start of the study.
  • No vaginal sexual intercourse within 72 hours before the study visit.
  • Has had at least 6 menstrual periods in the past 12 months.

Exclusion criteria

  • HIV infection.
  • Positive diagnosis for chlamydia or syphilis at screening or within 4 weeks prior to screening.
  • History of hormonal disorders or menstrual cycle irregularities.
  • Metrorrhagia.
  • Pregnancy or breastfeeding.
  • Family members or close relatives of the clinical or scientific team.
  • Treatment with any medication for chronic inflammatory disease or chronic conditions (e.g., cancer, arthritis, transplantation) within the past 12 months.
  • Participation in an ongoing clinical trial.
  • Receiving or having received antibiotic treatment within the 4 weeks prior to the study.
  • Refusal to be informed in case of detected abnormalities.
  • Indistinct use of both tampons and menstrual cups.
  • Never having had vaginal penetrative intercourse.

Treatment and study plan

Samples collection (whole blood, urine, vaginal and cervical cells)

Other

During the clinical visit, samples will be collected from participants, including blood, urine, and vaginal and cervical cells. These samples will be used for a range of analyses, including determination of the vaginal microbiota composition and sequencing, cytokine profiling, and assessment of local immunity through flow cytometry using CyTOF technology. Urine samples will be analyzed for pollutants such as phthalates and bisphenol, while blood samples will be used for blood cell counts.

Primary outcomes

  1. Determine the effect of the use of internal menstrual products on the composition of the vaginal microbiota.

    Time frame: Samples will be stored at -80°C and metagenomics sequencing will be performed within 24 months after collection.

    To investigate potential differences in microbiota between study groups, the investigators will perform metagenomics next-generation sequencing on vaginal swabs.

Secondary outcomes

  1. Comparison of the vaginal immune response of users and non-users of internal menstrual products

    Time frame: Samples for this purpose will be prepared for preservation immediately after collection. After preparation, they will be stored at -80°C and subsequently shipped for the analyses.

    Description of the cellular composition from vaginal and cervical samples (CyTOF technique) and measurement of vaginal cytokines.

    Since this is a cross-sectional study, all the measures are made at inclusion, i.e. at baseline.

  2. Effect of the type of internal menstrual protections on the presence of pollutants in urine.

    Time frame: Urine samples will be stored at -80°C and analysed within 24 months after collection.

    Quantification of parabens and other pollutants in urine samples or other samples.

Other outcomes

  1. Associations between the type of menstrual hygiene product used and sexually transmitted infections (STIs)

    Time frame: Statistical analyses will be performed after the last participant follow-up. They will be based on inclusion questionnaires. The time frame to evaluate the incidence of STIs will be the 12 months before inclusion.

    Retrospective epidemiological analyses will be performed using statistical modelling on the questionnaires filled in at the inclusion visit.

Study contacts

Contact information is provided by the study sponsor or research team.

Clinical team

CONTACT

[email protected]

Samuel Alizon, Dr

CONTACT

[email protected]

+33(4)144271667

Sponsors and collaborators

Lead sponsor

Centre National de la Recherche Scientifique, France

Other

Collaborators

  • Institut Alfred Fournier

Registry information

Official study title

Impact of the Use of Internal Menstrual Protections on Immunity and Vaginal Microbiota

Acronym: CUPS2

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Sep 30, 2025
Registry last updated
Apr 9, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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