I've posted about the newly arrived cat before. Turned up starving. Not managed to locate an owner, no chip etc.
She was very thin, and is putting on weight nicely. However, I have noticed her stomach seems round and firm. I noticed a few days ago that her nipples are more visible, I'd not seen them before.
She has become very playful (but then us only young, and was unwell with an infected wound when she arrived) she yowls and chirrups, she is grooming her stomach privates a lot. My other cat was tolerating her with occasional growls and side eye, but is now being more aggressive.
She hasn't been out in just over a month (since she arrived).