I guess the question is, what's the concern?
Kettlebells are weights, and kettlebell workouts, like any workouts, can be high intensity. Unless your doctor tells you otherwise, here's what I'd advise:
- feel free to keep up your usual workouts for now, but listen to your body. Don't push it if you don't feel well. Now is not the time to up the weight or intensity of your workouts.
- pregnant women's bodies produce a lot of relaxin, a hormone that makes your ligaments extra stretchy, which helps your pelvis change shape the way it needs to when you carry and birth a baby. The downside here is that relaxin doesn't make your muscles any stretchier. Be careful not to pull anything.
- watch your hydration.
As far as I know, you can keep working out as long as you want. I jogged until the seventh month if my uncomplicated pregnancy, and stopped largely because the sidewalks got icy. I felt way better that pregnancy then I did the time they put me on bedrest (for a placental positioning issue, so not like I was resting because I was sick). I saw a woman at the gym yesterday who had to be about 7 months pregnant, and she looked fab.