pooping cats

I have a question, my cat just had kittens maybe 2 weeks ago. the kittens are fine and so is she, however now the mother cat id pooping in the tub. not every day or all day just maybe twice or three times a week. now my question is what is making her do this? and why now? and yes her litter box stays clean and is assessable for her, unfortunately its not near where she and the kittens sleep but it wasn't a problem til now so I want to know what can I do to stop it.

You mean, she is pooping in the bathtube, not only in the litter as usual?

Im not sure, but I know some cats do poop and pee in the bathtube.  My reaction is its not the worst problem possible,  as its easy to clean off.  Unless you youself wants to bathe in there submerging the whole body in...   I myself usually just take showers in the bathtube, so for me personally it wouldnt be any great problem...

Im mean, some owners do allow it. And its not so much scooping of the litter.

The problem may be that the litter box is not near where they sleep...event though it wasnt a problem before, but now she has babies to take care of and cat mothers dont like to leave their babies unnatended for long...try moving the litter box closer to where they are. Good luck!

Bath tubs look like giant litter boxes to a cat, and I agree with Maxima, she may not want to be so far from the kittens. If at all possible try to put a second litter box somewhere closer, or move then all closer to the box. The only problem with not letting her go in the tub is that she may start going somewhere even worse, like on the carpet.  To stop her from going in the tub, I would leave a couple of inches of water in it. Good luck and keep us posted!