Is it bad to have two female pregnant cats around each other?
Until they have their kittens, pregnant cats don’t mind each other. And while some cats can successfully share the raising of kittens, others are not receptive to the idea and may kill or injure the other’s kittens, or reject their own. It’s always best to keep a cat with kittens away from other pets, strangers, and minimize your own interaction with the kittens to prevent issues. While some handling of the kittens is desirable for socialization, excessive handling prevents the mother from connecting with them and she may reject them.
Generally no. In fact, it is much more likely a problem to have a tomcat around. Tomcats will sometimes kill the kittens. There was an interesting study, it may have been an episode of National Geographic or Nature that I saw, about barn cats. It was not uncommon among barn cats (basically semi-feral domesticated cats that live on farms, kept to help keep the rodent population under control) for the females to form communities. Females would take care of each others’ litters, sometimes even nursing another cat’s kittens as well as her own. Toms were chased away by female cats, both mothers and “aunts” (female cats that didn’t have any kittens and were adults). I had a couple of friends in college who had two females who had kittens within a couple of days of each other; there was at least one tom who fathered a couple of the kittens in each litter (different mothers, same dad) and sometimes we weren’t sure whose kittens belonged to whom! They all got along just fine, the moms didn’t fi
