A system includes a control console, a laparoscopic instrument, and a uterine manipulator. The laparoscopic instrument includes a first proximity sensor element. The uterine manipulator includes a base and a shaft extending distally from the base. The shaft includes a distal end dimensioned to be inserted into the uterus of a patient and a second proximity sensor element located at the distal end. The proximity sensor elements are configured to cooperatively generate a distance signal indicating a distance between the proximity sensor elements. The control console is configured to receive the distance signal from either the first proximity sensor element or the second proximity sensor element and calculate a corresponding distance between the proximity sensor elements. The control console is configured to compare the corresponding distance with a threshold distance and generate an alert signal when the corresponding distance is smaller than the threshold distance.