Hi Pen - just had a moment to read back properly through your post and realised that you're actually carrying twins! Sorry hun, I hadn't noticed before.
Funneling with twins is actually fairly common, and much of the time is only because you are carrying two babies (not usual, and our bodies aren't made for it), and not because you have a genuinely incompetent cervix. Also, yours had only begun to funnel at 21wks which means it had actually held out quite well agai st the weight of two (your uterus is carrying the equivalent of a 28wk singleton pregnancy). Although your stitch is an emergent one, the fact that it was placed well before dilation or significant shortening means it stands an excellent chance of working well for you sweet.
If worst came to worst, and your babies were to deliver before 30wks (which is not as likely as you might think), then twins have an advantage over singles in that mother nature matures their major organs faster in anticipation of a premature arrival! They often do better than a singleton of a similar gestation - tho I am still fairly confident that you'll make several more weeks yet honey
As regards Evie, her premature arrival was a complete shock after previously carrying my first baby to term. I did have an emergency stitch placed with her, but at 23wks and with a dilated cervix and membranes bulging it unfortunately only bought her an extra week in utero. Though I still wish I could have carried her to atleast 28wks, given her shaky start she is now a happy, healthy 8yr old with the most generous, loving nature. Apart from having a short sighted eye, and some very minor concentration issues (which she might have had anyway), she is fine. The preemie journey is a tough one, but it can have a happy outcome. You're not there yet, but if it does happen, at the end of a long and sometimes arduous road, the rewards are many.
I'd recommend total rest if you can lovely, lots of water (1/2 glasses an hr), and lots of hope
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I say this so often, but there are lots of ladies who make it despite having lost all hope and in recent months there have been a few multiple mummies with stitch (and some without) who have had a poor prognosis but have gone on to defy the odds.
My cervix was already weak at 12wks with my third, twin oregnancy and probably open when I was upright. Despite that, I carried big boys to term against all those odds. You can too my sweet, hang in there