I just had a premature labour at 21 week where I had an open cervix 3 cm and the sac was 6 cm in vagina without contractions. I would like to know if the cerclage was beneficial in this situation and what is the probability of having this complication in future pregnancy? And when should I prepare for another pregnancy? Thanks

Well of course the cerclage was done to prevent another miscarriage because the opening of the cervix was too big, which is why you are miscarrying. I suppose it will be beneficial the next time you get pregnant, once the fetus has grown the stitch will be taken out when it is less unlikely to come down.

Are you sure you don't mean the open cervix was 6cm and the sac was 3? That would make more sense as to why the stitch was put in place.