I took pole classes when I first found out I was pregnant. It was totally fine, at that point baby is the size of a seed so she doesn't get in the way. The only problem I had was I got nauseous from spinning on the pole so I just took some pretzels with me to munch on when it wasn't my turn on the pole.
You can pretty much do everything you did before you were pregnant, especially in the first trimester, including abs workouts. I was even doing handstands with no problem into my second trimester.