HSE is short for Hystero Sonografic Examination. This is a procedure used for demonstration of the tubes to be patent.
To become pregnant the natural way or following insemination, at least one of the tubes must be patent. The tubes can be obstructed following infection, and often the woman is unaware of having suffered from such an infection in her earlier life.
The examination is performed in the first part of the cycle, between menstruation and ovulation.