Hi Tina,
I feel you pain as I work in a similar setting,
I have a pelvic floor lecture and some of my own personal material I can share with you,
As a general rule like most things with ultrasound the measurements are only part of the picture and the clinical setting must be considered,
email me at stayintouch@birdultrasound.com.au and I will put the material in a dropbox for you,
Steve