Can someone explain the ovidrel trigger shot?

sara

Should I have a positive opk before the trigger? Or do opks not matter when being monitored and having the trigger? I'm cycle day 11 and yesterday I had a 16mm, 15mm, 12mm and a few 10mm follicles. I'm getting another scan tomorrow and wondering if I will trigger tomorrow. I didn't get a positive opk yet. I took femera cycle day 3-7