risk of uterine perforation

It is a hole

Increasing rigidity and tenderness indicates an increased likelihood of perforation and peritonitis.

The purpose of perforation depending on what one is talking about. In the case of oil well, the purpose of perforation is to allow the oil or gas to flow more easily to the wellbore to get it out of the ground.

Long term side effects are rare for this type of procedure, however there is a possibility of uterine perforation. Damages to some other internal organ is possible as well which can result in the necessity of a blood transfusion.