Yes, but...
Did you kickboxing before pregnancy?
You can continue doing any activity you did previously. Running, swimming, surfing, cycling, weightlifting, skating... Unless your doctor said otherwise because of any pregnancy issue like placental abruption for example...
Now if you were sedentary before getting pregnant, then it is best to choose lighter activities such as walking, slow bike rides... You won't learn how to kickboxing or weightlifting while you're pregnant. That sittuation is not safe for you or the baby.
So yes It's safe depending on the mother's training background.
Sent from my ASUS_Z012DC using Tapatalk