Today I will do 1shoot decapeptyl for ivf. I need 2know for what it is used&in case a mircle happened &got pregnant naturaly can this shoot affect preg?

Not used in USA. Decapeptyl is a gnrh agonist which is used in ivf, in europe / other countries. It can be a monthly depot injection, or daily subcutaneous injections. The daily version can be used to prevent you from ovulating before an egg retrieval, or in a microdose flare protocol for 'poor responders'. The depot version can be used before frozen embryo or donor egg cycles. Hard to get pregnant after this med.
Unlikely. Have your reproductive specialist doing ivf reassure you but it is to get you pregnant and not there when you are pregnant.