Rancid

I know this seems dumb, but I can't find an answer on Google or yahoo answers. I want to know if anyone else has persistent rancid gas over an extended period of time while being pregnant. I'm obviously not pregnant being a man, but my fiance is. She's almost 26 weeks and over the last 3 to 4 weeks it's been absolutely awful and I want to know if this is common from pregnancy. Diet changed and her doctor says her and Baby Jack are very healthy. I Googled it, with no definitive answer.