Job interview, should I tell them Im pregnant or not?

I wrote about this before but now is real and I'm very nervous, my job interview is coming next week and Im 22 weeks pregnant. I dont even know what to do, Im confuse. Should I tell them that I'm pregnant at the interview or not? If I dont tell them at the interview I was planning to tell them 2 weeks after hired and explain to HR that I didnt know I was pregnant since Im irregular and that am sorry about it but I'll be worried about how this could affect the relationship between me and my future manager at work, if they hired me. What should I do? What would you do in my case?? It is hard to tell Im pregnant specially is very cold and Im wearing a jacket. What should I do?