What would cause free pelvic fluid (found on trans-vag us) in post menopause on hrt?

Cyst: Most likely this is normal but you could have a ruptured ovarian cyst.

Probably normal: This depends entirely on why the ultrasound was done in the first place. In a 56 year old, an ultrasound would most commonly be related to: 1. Abnormal bleeding 2. Pelvic pain 3. Abnormal findings on an exam free fluid in the pelvis can be normal, could represent a small amount of blood from the uterus (through the tubes) or fluid from a cyst rupture. Talk with your doctor about this!