A system for accessing a patient's uterine cavity and detecting perforations in the uterus includes an elongated probe having a flow channel extending to a terminal outlet in a distal region of the probe. A fluid source is coupled to the flow channel, and a seal on the probe is positionable in an endocervical canal. The probe may be trans-cervically inserted into the uterine cavity, and a fluid may be introduced through the channel to flow outwardly from the terminal outlet into the uterine cavity. A parameter of said fluid flow is monitored to detect a perforation in the uterus.