If my wife is pregnant at the interview will this delay the visa??

It shouldn't have any affect on the visa but will have an affect on travel if she is into the last part of the last trimester.

If there's any obvious reason the Consular officer might think its not your baby, maybe. Otherwise, as long as the visa is issued soon enough that your wife can travel and arrive in the US before giving birth, there should be no problem. If the visa or her travel is delayed for any other reason, you could be in a world of hurt. If that baby is born outside the US, your reunion with your wife is going to be delayed, visa or not.

I have heard stories of them waiting til the baby is born to check the DNA before issuing the visa. Anyone out there ever hear of anything like this. The night that it must of happened was the first week of June 2007. She should be about 4 months pregnant at the time of the interview.

Oh my gosh chill out and relax. You will be fine. I have had several friends on here whos wifes were pregnant and they were fine. One friend had there baby 3 weeks after her arrival in the states. PLEASE RELAX!!! They will no if you guys are legit. I know hard it is to relax but its best not to add any stress to your life.

Thank you Belwin!!

Yes, I agree with Belwin. Do not worry. Different airlines have different rules about carrying pregnany women in long haul flights. Some Airlines do not allow women above 28-week pregnant in long haul flights. But British Airways allows pregnant women upto 36-week to fly in long haul flights, if the pregnancy is normal and has no complications. You do not have to worry about it, since your wife will be 4 months' pregnant during the interview. But you should notify the Embassy in advance that your wife is pregnant, plus have your wife take a letter from her physician about her pregnancy. It will be really helpful, if it is a normal pregnancy. I think, it is a plus point for your case. Do not worry about DNA tests and all negative thoughs.

my sister in law never had a problem with her 9 weeks pregnancy in her interview
she immigrated long back and the embassy never gave her any hard time .

Thank you very much for the info. and you to Doc cute.

I promise you, it will be fine. The pregnancy wont stop they from giving her the visa, be it 9months.

Thanks.