did the vet check her for a UTI ? i'd assume they probably did, but if not, that'd be my suspect.
do they share a single litterbox?
i'd also think maybe your hormones are stressing them, especially as you're getting closer to your due date (congrats!). it's also possible that something happened while you weren't home that could have triggered a fear response... it's really hard to say =/
do they share a single litterbox?
i'd also think maybe your hormones are stressing them, especially as you're getting closer to your due date (congrats!). it's also possible that something happened while you weren't home that could have triggered a fear response... it's really hard to say =/