Diatomaceous Earth for deworming pregnant cat?

I already have food grade diatomaceous earth that I use to treat my hamster's mites. The internet said I can also use it for deworming cats. I'm pretty sure my cat is pregnant (I've owned lots of female cats that at one point got pregnant so I know how to recognize the signs by now). She's had worms for a while before she got pregnant and I've been treating her with worm meds but now that she's pregnant I can't give those to her. I read that diatomaceous earth is perfectly safe for pregnant cats to deworm them.

How much should I feed her, and how often? Can I mix it with things other than wet food? I can't really afford to buy some every day. Could I mix it with milk or maybe shake it up with the dry food?