Can you give a little more information? Is the doe doing it in the nestbox or while the kits are out and about? What breed?
We never had a big problem with this. I had a Himalayan that was very stressed out and was stepping on the kits. We also had a Brit who abandoned her kits and then kept running over them...obviously not a good mom (and got rid of her). At 4 weeks your kits aren’t newborns anymore...if it looks like your doe is doing it intentionally or doesn’t seem to care that she’s doing it, you probably shouldn’t breed her again.
Make sure the space that mom and the kits are in is big enough so the kits and/or mom can get away from each other. Once kits were getting out of the nestbox we would turn it on it’s side so the doe could get away from the kits...they can be pretty persistent when they want to nurse.