One of my friends is in a family way, and this is her second child, in her womb. She feels itching on her belly and she ioften avoids scratching her hand there, as someone told her that if a pregnant lady moves her fingers around the belly, they will leave permanent scars, I mean signs. Even her mother and elder sister do have such scars of fingers as they too have done so.

Is there any reality behind this myth? Or, is there any other reason behind the signs?

That is nothing more than a myth.

The "scars of fingers" you are talking about are called stretch marks. They happen to about 90% of pregnant women whether they scratch their abdomen.

The reason your friends belly is itching is because the skin there is dry. Tell her to drink plenty of fluids and use lotion on her belly.

It's very interesting to learn new myths from across the globe.

Just a myth, nothing to it.