Talk to Gynecologist on Pregnancy And Complications

I have 2nd pregnancy. first pregnancy I delivered at 34 weeks. in this pregnancy I had some complications.in start I faced bleeding issue then short cervix length. now I'm 27 week +5 days pregnant. my issue is Dr told me your internal os is open and cervix length is 3.2cm. she suggested me bedrest with medications.I want to know how much chances for premuture delivery? how many weeks easily go through? what could be complications that can I face? kindly guide me properly I'm really tensed. thank you