A cervical stitch may help to prevent the cervix from opening up, leading to miscarriage or early labour and delivery. Usually a stitch is inserted if there are suggestions of a shortening cervix, or if there is a previous history of early cervical dilation, or if you have previously had treatment to the cervix putting you at greater risk of a weakened cervix in pregnancy, for example a previous cone biopsy of the cervix following abnormal cervical smear.