I did aquaaerobics with my last pg & in this one, 0-2 times/wk. I haven't heard or been told of any scares about chlorine, I was given the go-ahead by my obgyn b4 i started. The only thing the instructors say is to limit ur leg movements, u can do the arm mvmnts but dont full on jog or anything, take it easy, as u dont want to incr ur heart rate too much & cook ur bubba.