The Tampon Test as a Primary Outcome Measure in Provoked Vestibulodynia: A Mixed Methods Study

Background: Provoked vestibulodynia (PVD) is characterized by severe pain, often induced by penetrative sex. This may lead to women abstaining from sexual intercourse, hence the recording of pain intensity levels in PVD research is often challenging. The standardized tampon test was designed as an alternative outcome measure to sexual intercourse pain and has frequently been used in clinical studies. Aim: The aim of this mixed methods study is to evaluate the tampon test as a primary outcome measure for an upcoming randomized clinical trial for women with PVD. Methods: An explanatory sequential design was applied, integrating quantitative and qualitative methods. In phase one, pain intensity levels were evaluated with the tampon test amongst 10 women, aged 18-33, with PVD. The test was repeated on day 1, 7 and 14. Pain intensity was rated on the Numerical Rating Scale (NRS), (0-10), 10 being worst possible pain. In phase two, the participants' experiences with the test were explored with semi-structured interviews using a descriptive and inductive qualitative design. All participants were recruited from the Vulva Clinic, Oslo University Hospital, Norway. Outcomes: The tampon test data and interviews were brought together to see how the interviews could refine and help to explain the quantitative findings. Results: The tampon test data demonstrated large intra- and inter-individual variability. Median tampon pain intensity was 4.5 (min=1.7; max=10; Q1=2.5; Q3=6). Many experienced the test as an inadequate representation of pain during intercourse as it was less painful, different in nature and conducted in an entirely different context. Four participants had a mean score of four or lower on the NRS, whilst concurrently reporting high levels of pain during sexual intercourse. Clinical Implications: The findings indicate that the tampon test may underestimate severity of pain among some women with PVD. Participants with low pain scores would be excluded from studies where the tampon test is part of the trial eligibility criteria, even though severe pain was experienced during sexual intercourse. Large intra-individual variability in pain scores also reduces the test's ability to register clinical meaningful changes and hence necessitates repeated measurements per assessment time point. Conclusion: Although the tampon test has many advantages, this study indicates several potential problems with the application of the test as a primary outcome measure in PVD. In our opinion the test is most useful as a secondary outcome, preferably undertaken repeatedly in order to increase precision of the pain estimation. Copyright (C) 2021 The Authors. Published by Elsevier Inc. on behalf of the International Society for Sexual Medicine.