false pregnancy

hello, could anyone give me any info on false pregnancy in cats? i took my female seal PT to the vet a few days ago because her stomach felt funny to me ( swollen ) and he said it was false pregnancy, i haven't bred her yet but her sister is pregnant ,could she be jealous ? i'm thinking not but i'm confused as to what causes this...
thanks
Jodi

It's possibly for many of the same reasons false pregnancy is caused in humans - I know nothing about it in cats but I am surprised your vet didn't explain it to you in a little more detail...perhaps you could phone and ask for some more information?