This manuscript describes the procedures to perform anogenital distance (AGD) and perineal measurements standardized by the Pelvic Organ Prolapse Quantification System (POP-Q): perineal body (PB) and genital hiatus (GH). These measurements are compared in women with and without pelvic organ prolapse.
This method can help answer key questions in the epidemiologic and urogynecologic fields about the clinical reproducibility of perineal measurements and their usefulness in describing perineal anthropometry. The main advantage this technique has is that the measurements are easy to learn from visual demonstrations. Begin by helping the patient into the lithotomy position with the thighs at a 45 degree angle to the examination table.
Select a digital caliper with a resolution length of 0.0005 inches and close the device, confirming that zero'appears on the display. Select millimeters'as the unit of measurement. Measure the ano-clitoral distance from the anterior clitoral surface to the upper verge of the anus.
Next, measure the ano-fossa distance from the posterior margin of the hymen to the upper verge of the anus. To improve the interobserver accuracy, have a second examiner perform each measurement three times to obtain a total of six measurements per examiner for each non-invasive anthropometric measurement. Then, use the average value of both sets of measurements as the true estimate of each anogenital distance and subsequent analyses.
Disinfect the calipers. For pelvic organ prolapse quantification, use a measuring tool with centimeter markings to measure the genital hiatus from the middle of the external urethral meatus to the posterior margin of the hymen to the nearest half centimeter three times. Then, measure the perineal body from the posterior margin of the hymen to the mid-anal opening three times.
Use the average of both sets of measurements in subsequent analyses. In this representative study, significant differences were observed in the age, number of deliveries, and birth weights between the patients and the control study participants. Notably, there were significant differences between the ano-clitoral and ano-fossa distances in the pelvic organ prolapse patients compared to the control participants.
The length of the genital hiatus was also longer in the pelvic organ prolapse patients than in the control participants, with no significant differences measured in the perineal body distances between the two groups. We found differences between the AGD, ano-fossa length, which is shorter in cases of prolapse and the AGD, ano-clitoral and genital hiatus lengths, which are longer in women with prolapse. Our data suggests that the anthropometric characteristics of the perineum, such as a shorter AGD ano-fossa length that could be determined prenatally, may be an independent etiological factor for predicting pregnant flow dysfunction.
Further investigations are needed to evaluate the comparability of AGD and POCU measurements. It could be beneficial to universalize the measuring instruments and the accuracy of the method to guarantee a comparability of the measurements between different working groups and to minimize the visual bias between observers.
