Progesterone suppositories

Has anyone had to do this? I am 24 weeks & my cervix is short. The Drs have been watching for a while now. It isn't below what they call high risk but enough to keep them concerned at 2.1. So they put me on progesterone suppositories once a day & I'll continue to do this to prevent going into early labor until around 35 weeks. Just wanted to know if anyone else has had to do this & what side effects there are? Also if it worked for you?