My first pregnancy I wasn't on progesterone pessaries and had repeative bleeding at 5,7,9,12,14 weeks finally my membranes gave way at 16 weeks either due to the bleeds or IC,
My second pregnancy I was on Progesterone 2 a day and had no bleeding but my membranes gave way at 20 weeks due to IC.
3 rd Pregnancy on progesterone and was stitched at 13 weeks to prevent IC.
There has been studies done on progesterone support and PCOS, my obst would not let me off them till 14 weeks.
There has also been an increasing amount of women with PCOS and Incompetant Cervix's which there is currently a study being done. It takes so long to fall pregnant at least cover all bases and discuss it with your treating doctor, and a boodtest doesn't hurt nor does an ultrasound
Good Luck
Bec