The Effect of Pessary Insertion on Pelvic Anatomy: A Prospective Observational Study Using Upright MRI

To determine the anatomical effect of pessaries in the upright position in women with pelvic organ prolapse (POP).

Prospective observational cohort study.

Outpatient clinic of our gynaecology department.

Fifteen POP patients with successful ring-shaped pessary use.

Upright magnetic resonance (MR) images of the pelvis were acquired before, immediately after insertion of their pessaries, and 1 week later.

Distances from the lowest points of the bladder, cervix, and pessary to the pelvic inclination correction system (PICS) line were measured, as well as the angles of the uterus and pessary relative to the PICS in the midsagittal plane.

Pessary insertion lifted the bladder's lowest point from 0.1 cm below to 0.6 cm above the PICS (p = 0.015), but it descended to 0.2 cm above the PICS 1 week later (p = 0.334). The cervix was lifted from 0.0 to 2.5 cm above the PICS (p < 0.001), which persisted after 1 week (p = 0.470). The angle between uterus and PICS increased after insertion from 97^o to 115^o (p = 0.008) and remained stable (113°, p = 0.198). Pessary position changed from 0.7 to 0.3 cm below the PICS in 1 week (p = 0.020); the angle did not change (56° to 54°, p = 0.820).

Pessary insertion changes the pelvic organ position and angulation. After an initial lift, the effect on the bladder diminished after 1 week, while for the uterus it remained. This may suggest a role for uterus lift in relieving POP symptoms.