3 miscarriages,,, please give me some ADVICE PLEASE

Kaʏʟa* • 3 miscarriages 😢
I had my first miscarriage in Dec 6,13,,, I had my second miscarriage in Nov 14,14 and,,,I had my third miscarriage in Nov 12,15,, and now the doctor told me if I get pregnant again I will have to get my cervix stitch and I'm scared I don't know what to do if that really do work or why do people have miscarriages