Tampon test measurement properties in women with provoked vestibulodynia: baseline data from a pragmatic randomized clinical trial.

INTRODUCTION: Provoked vestibulodynia (PVD) is a common cause of dyspareunia in young women. Because intercourse-related pain cannot be assessed consistently in all affected women, the tampon test (TT) is often used as a standardized proxy for insertional pain. This study aimed to evaluate within-person variability, measurement precision, and convergent validity of the TT, and to describe baseline sociodemographic and clinical characteristics of women enrolled in a pragmatic randomized clinical trial of PVD.

METHODS: Women aged 18-35 years with diagnosed PVD completed baseline questionnaires and 3 standardized TT assessments over 1 week. TT pain was rated on a 0-10 numerical rating scale (NRS). Baseline characteristics were described for the total sample and stratified by PVD onset type. Systematic change across TT repetitions, minimal detectable change at the 95% confidence level (MDC95), and correlations between TT pain and recalled pain during last intercourse were examined.

RESULTS: Eighty-six participants completed baseline assessment. Median age was 26.5 years, median symptom duration was 6.0 years, and 40% had primary PVD. Participants showed substantial symptom burden, including impaired sexual function, elevated psychological distress, and reduced health-related quality of life. Women with primary PVD reported higher TT pain than women with secondary PVD, whereas most other baseline characteristics were similar. Mean TT pain decreased slightly across repetitions from 5.1 to 4.6, although approximately 30% of participants showed fluctuations of ≥2 NRS points. Measurement precision improved when repeated TT scores were averaged: MDC95 decreased from 3.8 for a single TT to 2.7 for the mean of two tests and 2.2 for the mean of three tests. TT pain correlated moderately with pain during last intercourse (r = 0.46-0.49).

DISCUSSION: Women enrolled in this pragmatic PVD trial showed substantial symptom burden and clinical heterogeneity. Repeated TT assessments improved measurement precision and may therefore be preferable when insertional pain is used as an outcome in longitudinal PVD studies, particularly when evaluating within-person change or individual treatment response. TT pain showed partial convergent validity with recalled intercourse pain, but the 2 measures should not be considered interchangeable.