Cervical stitch

Hey guys ! Wondered if anyone on here has cervical stitch or have had one and when you got it taken out how long after did your labour start!! I’ve had to prem babies and I had cervical stitch with both but the first one they put it in to late my waters broke and second I caught an infection that sent me into labour. This is furthest I’ve carried im 33 weeks Monday :) the stitch is working so good so far. I had my cervix checked other day and it’s shortened quite a bit it was 25mm now its 13mm so I’m bit worried 😟