Measurement of vaginal length: Reliability of the vaginal sound--a Gynecologic Oncology Group study

A decrease in vaginal length associated with treatments for gynecological malignancies, particularly pelvic radiotherapy, negatively impacts sexuality. Research into this important problem has been hampered by a lack of instrumentation to measure vaginal length. The Gynecologic Oncology Group recently evaluated the reliability of an instrument, the "vaginal sound," designed to measure vaginal length. Eighty-eight physicians and nurses attended a training session in the use of the vaginal sound that included a clinical practicum with live models. Reliability was assessed at the time of the practicum. The instrument performed well, with vaginal lengths in models without cancer in the upper range of normal as documented by Masters and Johnson. The vaginal sound also appeared to be sensitive to hypothesized changes in vaginal length. Interrater reliability was high with intraclass correlation coefficients of 0.88 among instructors and 0.76 among trainees. In conclusion, the vaginal sound is a simple, yet reproducible measure and adds methodologic rigor to studies of vaginal length.