To see if blocked. Essure provides sterilization by using small flexible microinserts which help the tubes to naturally occlude. Three months alter an hsg is ordered to confirm that the tubes are blocked. This has allowed essure to have the lowest failure rate. Some are investigating the use of sonograms done in the office to take the place of the hsg confirmation test, but not yet approved by fda.
Confirm occlusion. You need to ensure that the tissue has grown adequately around the implant to block the tube, sometimes it can take longer than 3 months. If the tube is not closed at 3 months the hsg has to be repeated at 6 months.