Reusable menstrual hygiene products may lead to underdiagnosis of heavy menstrual bleeding: a randomised trial.

Background: Clinical diagnosis of heavy menstrual bleeding (HMB) is dependent on patient report of menstrual product usage of pads and tampons, but it is unknown if newer reusable menstrual products (cup and underwear) are similarly diagnostic.

Methods: We enrolled 20 regularly menstruating individuals with HMB for two menstrual cycles. Participants completed a retrospective baseline Pictorial Blood loss Assessment Chart (PBAC) at the time of enrolment (eligibility PBAC score ≥100) as well as several different measures with each study cycle. In cycle 1, participants used study-provided disposable pads and tampons. For cycle 2, participants were randomised to menstrual cup or underwear and collected their menstrual fluid on their heaviest 2 days. We compared the two cycles with respect to the weight of menstrual fluid collected and the frequency of product changes and leaks during the heaviest days in cycles 1 and 2, as well as questionnaire responses.

Results: Overall, the mean rate of product changes per heaviest day were 5.5 disposable product changes (range 1.5-11), 3.6 cup changes (range 1.3-6.2), and 3.5 underwear changes (range 2.7-6.9). Both groups (cup users and underwear users) reported a median 3.5 leaks (range 1-5) per heaviest day in cycle 2, while using the menstrual cup or underwear.

Discussion: Participants reported fewer daily changes of reusable products compared with disposable ones, but more leaks, suggesting that 'rate of product change' with reusable products may result in missed diagnoses of HMB.