I was my mum's first baby and I was 7 weeks early due to her "incompetent cervix".
2 years later she had a miscarriage due to the same. I am no sure at what stage, I think about 4-5 months.
18 months later she had a "cervical stitch" to keep my sister in place, who was born by caesarean at 39 weeks as Mum couldn't hang onto her anymore.
I am 30 weeks pg with my first and am wondering if this condition could be ? I have asked my mw who was vague and noncomittal. I have looked on www which seems to say that there is no way of telling, until you've had an early baby or mc, unless you've had a multiple birth.
My mum had me at 32 weeks, incompetent cervix too (this still pisses her off a bit, she thinks it was just a catch all term in those days as these days they won't diagnose it until you've had more than one pre term delivery). My ds (now seven months) was all of 6 days early and my sister's three dcs were all late. Totally unscientific sample I know but I hope it helps. My mum says that with all of our pregnancies she was on tenterhooks till we got past 32 weeks!
The risk time is normally Mid-T with IC, I was tested during weeks 20-24 and they're starting from week 16 this time. If you are worried ask if there is any chance of having cervical length scans as that will tell them as soon as you start to show any signs.
A cerclage is normally removed not far from where you are now anyway (they sometimes don't remove them, if they think a CS would be safer and remove them during the op).
Don't know if this helps but my mother had me 10 weeks early. When I was pregnant with my daughter my mother worried that I would go into premature labour as she was convinced it was "genetic" in some way. However my daughter was two weeks overdue and nearly had to be induced!!