Telling your interviewer you are pregnant

I was at work the other day and an owner for a big company came in and said that they would love to have me join their company I went through a huge interview process and I was just so nervous I couldn't spit out that I was pregnant well I am talking to the owner today on a conference call with another person and I really need to tell them that I'm pregnant but I'm so nervous that they're going to tell me nevermind as soon as I tell them that I'm expecting I feel like they shouldn't judge me because I am pregnant they love me and I feel like they would still give me a job but I just don't want to be shut down again I know a lot of companies do not want someone who is pregnant I'm due in December so it's going to come quickly and I know that I have to tell them but what would you guys do I want to wait until I am officially with their company before I tell them