About cervical stitch

I had an abortion in my first pregnancy at 5th month due to transvaginal scan which conducted on march 14th 2016, upto that dat day i don't have any problem in my pregnancy and at that time amniotic fluid was 13cm, the next day my amniotic fluid started to leak upto morning amniotic reached 5cm so my doctor did medical abortion through normal delivery.... now i am 4th month pregnant, due to fist abortion my doctor suggested me cervical stitch so is it necessary ??? what is the risks n precations associated with cervical stitch, i am very much worried thinking about this, please help me about this