Systems and related methods for measuring pelvic organ prolapse are disclosed. A plurality of positioning devices, such as RFID tags, ultrasound reflectors or magnetic field sensors, which may be active or passive, and which are preferably disposable, are set at predetermined positions within the patient and their relative positions recorded with one or more corresponding external receiving devices fixed to the patient while the patient is in a relaxed state. The patient is then instructed to perform an action (such as a valsalva maneuver) that causes the positioning devices to move and their movement relative to their initial recorded positions is measured.