Proceedings of the 2020 Design of Medical Devices Conference DMD2020 April 6, 7-9, 2020, Minneapolis, MN, USA

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DIMENSIONAL DATA ON VAGINAL ANATOMY: MEDICAL DEVICE DESIGN BARRIER

Avery Smith1 Ada-Rhodes Short2 Uccellini LLC Uccellini LLC Bend, OR, United States Bend, OR, United States

ABSTRACT 1.1 Method An accurate understanding of anatomy allows designers We used EBSCO and Google Scholar as the databases and scientists to create medical devices that work well for their for surveying available studies on vulva vaginal dimensions market. However, reliable descriptions of vulva vaginal [1,2]. Search terms included: “vulva dimensions”, “vulva dimensions are not currently available for reference. This measurements”, “vaginal dimensions”, “vaginal measurements”, literature review attempts to survey the existing data collected “ dimensions”, “labia measurements”, “clitoral on vulva vaginal dimensions and report the findings. We located dimensions”, “clitoral measurements”, and “vulva cross- scholarly journal articles and cross-sectional studies via sectional study”. When a potentially informative data set was not academic databases and online search engines. To pinpoint the published publicly, or not published in completeness online, a data that would be helpful in dimensional analysis of vulva request for distribution was submitted using an interlibrary loan vaginal measurements, key search terms included: “vulva program. All requests were approved, and the full texts were dimensions”, “vulva measurements”, “vaginal dimensions”, received. Papers and studies specifically looking at the genital “vaginal measurements”, “labia dimensions”, “labia anatomy of infants or fetuses, were not included. The relevant measurements”, “clitoral dimensions”, “clitoral documents were read, annotated, and cataloged in reference measurements”, and “vulva cross-sectional study”. management software [3]. Sample sizes, inclusion criteria, exclusion criteria, measurements, age range, race and ethnicity Keywords: Vulva vaginal, Medical devices, Designers, information are all metrics that were recorded and compared Dimensional Analysis, Anatomy, Survey. between each study in a spreadsheet.

1.2 Results INTRODUCTION The most extensive and best data set available surveyed In this study, we used academic databases and online search 657 white women aged 15-84 [4]. The data was broken up into engines to locate available studies on vulva vaginal decades, and measurements were tabulated for the 5th, 50th, and measurements. We anticipate there to be limited raw data 95th percentile of each decade. This data set is by far the best available for use by professionals interested in designing medical available resource due to its large sample size and the variety of devices interacting with female genitalia. The available data measurements collected. However, the raw data from this study collected was not viable as a general reflection of the female was not published, so the measurements and distributions could population due to small or homogeneous samples. Due to the not be stratified by someone without direct access to the study’s deviation in measurement tools and protocol, there is expected results. Another limitation to the utility of the data collected, as to be a substantial variation between studies on the exact acknowledged by the paper, is that the study population was numerical dimensions reported. ethnically and geographically homogeneous [4].

1 Avery Smith is currently a student at Oregon State University 2 Contact author: [email protected].

V001T08A002-1 Copyright © 2020 ASME Table 1 lists all vulva vaginal dimension data sets that were discoverable using EBSCO’s academic database from 10.21.19 - 11.7.19. We excluded studies specifically aimed at gathering data regarding the genital anatomy of infants and fetuses. For ease of reading, Table 1 has been formatted in landscape orientation on the following page. Downloaded from http://asmedigitalcollection.asme.org/BIOMED/proceedings-pdf/DMD2020/83549/V001T08A002/6552698/v001t08a002-dmd2020-9025.pdf by guest on 24 September 2021 Table 2 lists the mean and standard deviation values for clitoral length, clitoral glans length, clitoral glans width, distance from to , length, length and width, perineum length, vaginal length, and measurement tool used. We recorded the values from studies that observed women of age 18 years or older in Table 2. The reason for excluding data sets covering a majority of minors is that there are clear and obvious reasons behind the substantially lower mean values for those measurements. Studies that measured vulva vaginal dimensions, but reported one or fewer of the specific measurements listed above, were not included in Table 2. The purpose of showing these dimensions is to showcase the variation present in published data sets. For studies that analyzed and reported mean and standard deviation values separately between groups (such as parous versus nulliparous, or pre and postmenopausal women), the mean and SD averages were taken for the whole cohort and reported [7]. Table 2 can be found on page 5.

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Study Citation Sample Ethnicity / Race Age Vulva - Vaginal dimensions collected Size (yrs)

Kreklau et al. 2018 Clitoral length and width, Distance of clitoris to urethra, Introitus opening, Length of perineum, 657 100% white 15-84 [4] Length of labia majora (left and right), Length and width of labia minora (left and right)

Lloyd et al. 2005 74% - white, 10% - asian, Clitoral length and width, Clitoris to urethra, Labia majora length, Labia minora length and [5] 50 12% - black, 2% - mixed, 2% 18-50 width, perineum length, vaginal length, tanner stage, colour of genital area compared with - -latin american surrounding skin, rugosity of labia

Clitoral length and width, Length and width of right and left labia, Distance from hiatus to anus, Haim et al. 2016 [6] 32 n/a 20-51 Distance from urethra to hiatus, Distance from urethra to clitoris, Distance from hiatus to clitoris, Length and width of hiatus, Depth of posterior fornix and anterior fornix.

Brodie et al. Clitoral length and width, Length of labia majora, Length and width of labia minora, Distance 100 n/a 21-60 2008 [7] from clitoris to urethra, Perineal Length

Veale et al. 2013 [8] 55 48-White, 2-Mixed, 3-Other 18-60 Width of labia minora

umbilicus to pubic hairline / skin fold top of mons , top of the mons pubis to the end of the labia majora, top of the mons pubis to the cleft, length of the labia majora (cleft to end of labia), Seitz et al. 2010 [9] 15; 13 n/a 26-95 lengths of the side segment lines (end of the labia majora along the inguinal crease up to the lateral hairline at the femoral vessels b), lengths of base of mons triangle, inguinal crease / pubic hairline angle ° , inguinal crease / labia majora angle

Lykkebo et al. 2017 Labia minora length, Perineum length, Left and right labia minora width, mean width left and 244 100% - white 18-50 [10] right

Clitoral glans length and width, clitoral prepuse length, clitoris to urethra, Urethra to , Cao et al. 2014 [11] 319 100% - Chinese 18+ Vagina to perineum, Perineal body length, Labia minora length and width, Labia majora length and width, apex to clitoris glans, apex to perineum

Weber et al. 1999 [12] 81 n/a 28 - 72 Vaginal length

Akbiyik and Kutlu 1 mo - Clitoral length and width, labia majora length, left and right labia minora length and width, 205 n/a 2010 [13] 10 yrs perineal length

99% - White Verkauf et al. 1992 [14] 200 n/a Clitoral size 1% - Black

Köşüş et al. 2016 [15] 67 100% turkish n/a Clitoral length, and labia minora length and width

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90% - White Oakley et al. 2014 [16] 30 n/a Clitoral size and location 10% - Other 22.7% - - Hispanic 72.7% - non - Hispanic 5% - unknown length, Clitoral diameter, length of labia minora, clitoral hood to urethral orifice, Brodie et al. 2019 [17] 44 10-19 9% - African American width of labia minora, clitoral hood to lower border of 86.4% - white 4.5% - other

length of clitoral hood, length of sides of clitoral hood, clitoral diameter, apex of clitoral hood to Brodie et al. 2016 [18] 58 n/a 0-16 base of pubic symphysis, apex of clitoral hood to urethral orifice, distance of clitoral hood to labia majora, and length and depth of labia minora

Chalmers et al. 2014 clitoris length and width, length from clitoris to anus, clitoris to urethra, clitoris to posterior labia 56 n/a <2 - 13 [19] majora, mucosa behind vagina or posterior fourchette, and radius to labia minora at vagina

Battaglia et al. 2018 ultrasonographic translabial clitoral volume and labia minora thickness measurements and color 18 100% Caucasion 25-35 [20] Doppler assessment of the dorsal clitoral and posterior labial arteries Table 1, Cataloged studies, population demographics, and measurements taken

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Mean values [Standard Deviation] (mm)

Study [1] [2] [3] [4] [7] [8] [11] [12]

Clitoral length - 19.1 [8.7] 13.3 [6.7] 17.45 [9.5] - - 5.1 [1.4] 2 Clitoral glans length 6.89 [4.96] - - - - 5.04 [1.74] - - Clitoral glans width 4.62 [2.54] 5.5 [1.7] 3.9 [1.7] 10.25 [5.85] - 4.14 [1.22] 3.4 [1] - Clitoris to urethra 22.63 [7.66] 28.5 [7.1] 31.7 [9.8] 28.95 [8.3] - 24.95 [4.37] - - Labia majora length 79.85 [15.34] 9.3 [1.3] - 85.85 [12.35] - 75.71 [5.22] - - Labia minora length 42.53 [16.32] 60.6 [17.2] 3.64 [1.37] 53.8 [11.65] 42.8 47.99 [5.82] - 3.6 Labia minora width 13.77 [7.76] 21.8 [9.4] 1.47 [1.9] 16.65 [4.4] 15.7 20.59 [8.59] - 1.7 Perineum length - 31.3 [8.5] - 30.7 [9.95] 24.3 24.56 [4.20] - - Vaginal length - 96 [15] 94.4 [13.3] 86.3 [13] - - - - disposable paper disposable tape disposable tape disposable tape disposable tape stainless steel disposable tape Measurement tool Plastic Calipers measure measure measure measure measure vernier caliper measure Table 2 Comparative Measurements

V001T08A002-5 Copyright © 2020 ASME 1.3 Discussion devices, uterine sound, endometrial biopsy curette, vaginal At first glance, Table 1 may appear to showcase a list dilators, vacuum assisted delivery device, catheters, of valid and compilable data, but the table does not capture the menstruation products, and vaginal retractors [23]. variation and specificities of each study. It is difficult to group together this list of studies in any meaningful way because of the 1.4 Future Work variation present between each study, as shown in Table 2. The To minimize interobserver variation a standardized specific measurements recorded, method of taking said method of measurement protocol should be developed, Downloaded from http://asmedigitalcollection.asme.org/BIOMED/proceedings-pdf/DMD2020/83549/V001T08A002/6552698/v001t08a002-dmd2020-9025.pdf by guest on 24 September 2021 measurements, measurement tool utilized, and targeted attributes published, and made widely available. Researchers interested in of the subject groups, vary greatly from study to study. collecting and compiling data should adopt this documented Furthermore, raw data is published in almost none of these protocol. Standard measurement tools should be determined and studies, making the potential for independent statistical analysis explicitly stated in the protocol, as well as strictly adhered to by and continued data compiling void. all faculty conducting studies. We recommend a disposable measuring tape, as it seems to be the most commonly utilized Several of these surveys had varying inclusion and exclusion tool in the previously conducted studies, and because when criteria for their data sets. For example, one of the disqualifying compared to calipers, it may result in less physical discomfort criteria for the participants in the largest sample size study was for the subjects. vulvar complaints [4]. The definition of vulvar complaints was not expanded on, so we assumed this includes any female Large sample sizes with various racial and ethnic identities displeased with their vulva for any reason. This could lead to a should be surveyed and recorded to ensure data can be lack of dimension collection for women who have a poor genital generalizable. If significant differences in vulva vaginal self-image. Many women with labia minora that protrude out dimensions are present, the data should be clumped into from the labia majora believe their genitals to be “abnormal” due homogeneous racial and ethnic groups and used independently to the skewed depiction in pornography and media [21]. Another so that more accurate data is available for various identities. study conducted on women who were seeking could have potentially addressed this gap in data collection, but the 1.5 Conclusion only measurement documented here was the width of labia There are current studies available that serve as good minora [8]. starting points for dimensional reference when designing medical devices for the female external genitalia. Further studies The largest sample size study had an inclusion criterion of only and raw data sets should be conducted and shared to provide a white women [4]. This presents another hole in the dimensional broader basis and understanding of the range in anatomical information. The researchers made the intentional choice to variation and ethnic differences that can be expected. Concerted survey a racially homogenous group, knowing it would result in efforts should be made to ensure that medical device design is less unknown variability in their data. More studies would need not biased toward narrow and unrealistic labia minora to be conducted to collect generalizable data not specific to only representations in media, nor should the design be based on data white women. Racial and ethnic variables may have high sets only applicable to one racial group. Information collection impacts on vulva vaginal dimensions. Especially since an and utilization are key in creating health care resources that do ultrasound study has shown significant differences between not disadvantage specific groups or perpetuate social stigmas. white and black female pelvic organs [22].

Just as the dimensions measured were different between studies, so were the measurement tools. Most of the studies that reported their measuring tool state using a flexible measuring tape. Several other studies did not report the measuring tool employed, or used a different tool altogether, such as calipers or a digital imaging machine [11,16].

The accuracy and availability of this information is consequential for anyone designing medical devices relating to women’s external genitalia. Physicians, gynecologists, and medical device designers must have access to reliable anatomical data to inform their contributions to medicine and the wellness of the patient. Medical devices, for this report, will be defined as products that assist in user wellbeing as it relates to their health, both physically and emotionally. The following medical devices would be directly impacted by accurate or inaccurate anatomical data regarding the female vulva: speculum, douche, intrauterine

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