Pelvic Organ Prolapse Quantification (POP-Q) is a standardized examination of vaginal and perineal external measurements originally designed to objectively quantify pelvic organ prolapse. Currently, two of the external POP-Q measurements, gh– genital hiatus and pb– perineal body, are also used as an evaluation tool for patients with pelvic floor dysfunction. In pelvic floor rehabilitation, understanding the measurements and documentation of pelvic floor support can help with goal setting and treatment planning.

Significance of the External POP-Q Measurements

Measurements of gh and pb have been shown to identify patients who:

• Have a high probability of Levator Ani (LA) avulsion
• May respond poorly to a pessary fitting
• Are at risk for prolapse progression
• May have recurrence of prolapse after surgery

Taking the measurements of gh and pb helps physical therapists quantify introital gapping during our baseline evaluation and post treatment. Blomquist, 2018 reported that the genital hiatus size is a marker that might identify postpartum women at high risk of developing pelvic floor disorders with aging.

Specifically, the gh is the distance between the urethral meatus and the posterior hymen spanning the anatomical area around the introitus. The range of this measurement is between 1.5-8.5 cm. The pb is measured from the posterior hymen to the mid anus. The range of this measurement is 2.0-7cm.

Clearly, measuring these locations is important in patient care and rehabilitation of pelvic floor dysfunction.

POP-Q Measurement Techniques

All measurements (except the total vaginal length – tvl) are recorded in cm while the patient is instructed to perform a maximal strain held for six seconds. This strain is usually repeated three times. A marked cm stick developed specifically for the .5 cm increment measurements (several are on the market) is the easiest and most accurate to use. Self-made rulers from swabs, pap smear sticks, or tongue depressors have also been used for measurements but they may be more cumbersome for the clinician and markings may not be as accurate.

Determining Levator Hiatal Ballooning

Using the sum of gh + pb produces a number that represents the levator hiatus and defines the levator hiatal distensibility or ballooning. According to Khunda et al, 2012, excessive levator ballooning is present when the sum of gh and pb are > 7 cm. Ballooning can be classified as mild to severe. The data from the Gerges et al, 2013 study on determining the ballooning of the levator hiatus is summarized in the table below. A gh + pb measurement ≥ 8.5 cm may help to identify women with levator avulsion and those who are at increased risk of prolapse recurrence after reconstructive surgery.

To learn more about the POP-Q and its role in defining vaginal myofascial anatomy findings, take Kathe’s continuing education course Pelvic Floor Support Systems in Postpartum Recovery, Pelvic Pain and Prolapse.

For a complete review of the specific nine point objective measurement techniques see the free access article by Madhu, C., Swift, S., Moloney‐Geany, S., & Drake, M. J. (2018). How to use the Pelvic Organ Prolapse Quantification (POP‐Q) system. Neurourology and urodynamics, 37(S6), S39-S43.

References and Resources

American Urogynecology Society – free mobile app, the POP-Q Interactive Assessment Tool

Blomquist, J. L., Muñoz, A., Carroll, M., & Handa, V. L. (2018). Association of delivery mode with pelvic floor disorders after childbirth. JAMA, 320(23), 2438-2447.

Handa, V. L., Blomquist, J. L., Roem, J., & Muňoz, A. (2018). Longitudinal study of quantitative changes in pelvic organ support among parous women. American journal of obstetrics and gynecology, 218(3), 320-e1.

Dunivan, G. C., Lyons, K. E., Jeppson, P. C., Ninivaggio, C. S., Komesu, Y. M., Alba, F. M., & Rogers, R. G. (2016). Pelvic organ prolapse stage and the relationship to genital hiatus and perineal body measurements. Female pelvic medicine & reconstructive surgery, 22(6), 497.

Gerges, B., Atan, I. K., Shek, K. L., & Dietz, H. P. (2013). How to determine “ballooning” of the levator hiatus on clinical examination: a retrospective observational study. International urogynecology journal, 24(11), 1933-1937.

Handa, V. L., Blomquist, J. L., Roem, J., & Muňoz, A. (2018). Longitudinal study of quantitative changes in pelvic organ support among parous women. American journal of obstetrics and gynecology, 218(3), 320-e1.

Khunda, A., Shek, K. L., & Dietz, H. P. (2012). Can ballooning of the levator hiatus be determined clinically? American journal of obstetrics and gynecology, 206(3), 246-e1.

Lowder, J. L., Oliphant, S. S., Shepherd, J. P., Ghetti, C., & Sutkin, G. (2016). Genital hiatus size is associated with and predictive of apical vaginal support loss. American journal of obstetrics and gynecology, 214(6), 718-e1.

Ow, L. L., Subramaniam, N., Atan, I. K., Friedman, T., Martin, A., & Dietz, H. P. (2019). Should Genital Hiatus/Perineal Body Be Measured at Rest or on Valsalva? Female pelvic medicine & reconstructive surgery, 25(6), 415-418.

Volloyhaug, I., Wong, V., Shek, K. L., & Dietz, H. P. (2013). Does levator avulsion cause distension of the genital hiatus and perineal body?. International urogynecology journal, 24(7), 1161-1165.