A cerclage is to keep the cervix closed but it can be put in before any dilating has occured to prevent it from happening. I don't know if they can do one at 23 weeks tho. It is probably right on the boarderline.
In my second pregnancy, I was 4 cm dilated at 17/18 weeks. I had an emergency cerlage put in and made it to 33 weeks. I spent 16 weeks on bed rest at home. The cerclage was still holding but my water broke so they went ahead and induced.
In my first pregnancy my cervix was less than 1 cm thick so I was put on strict bed rest. I made it to 36wk5d. My cervix was still only slightly open but my water broke.
best of luck to you..
Victoria is correct. A cercalage is used to hold your cervix closed. Typically I think it does come with bed rest. Try not to worry. They will monitor you closely and these things tend to turn out just fine. Keep us posted on how your doing.
I'm only 15 weeks, so I haven't been measured yet. As for the cerclage, I believe it's for an incompetent cervix, one that is dilated. I hope some of these other ladies can offer a more knowledgeable experience. I'm sorry I couldn't be of much help, just try and hang in there knowing that even if you end up in the hospital it is what's best for you and baby.