May be early signs of labor. Have you had a vet check her to make sure she's pregnant (or not) and otherwise healthy?

Cheryl, female cats can reproduce as young as 4 months of age. Usually it is between 5-9 months when they reach sexual maturity but it can be sooner.
I would definitely get her spayed as soon as possible- vets can spay during a heat cycle and even if they are pregnant.
Some vets will charge more if pregnant or in heat at the time of spay.

Maybe hormone levels rose before she actually went into heat, making her nipples enlarge.

I cant help you , but just wanted to say I am glad you brought her in. I am sure she is too! ;D

annz has a good point...she might be ready to give birth. My older cat had enlarged nipples and a tummy when I found her. I suspected she was pregnant and had the vet take an x-ray, which they said showed she was not. Unfortunately, during her spay two weeks later, it turned out she had fetuses in side her, probably why she got dumped. I think there's a good chance your new kitty is pregnant. I hope your vet is better than mine at determining what's going on (I promptly switched vets). Good luck!

I don't understand. The vet estimated her age but did not identify her as being pregnant? What did I miss?

Boy, I feel like I'm missing something here too. Vet estimated age at about 1 year and shaved the cat to see if there was a surgery scar. No. She told me that I was doing the right thing (her words -I don't need to be talked into spaying but I do not want to do it if she's pregant.) I didn't think to pin her down on whether she is preg or not. Guess I thought she'd tell me, I don't know. So, whether pregnant or in heat, I'll be waiting for several weeks until the mystery is solved. I guess another possiblity is that she had a litter not long ago and is in heat again? I find no signs of milk, just the elongation. One thing is for sure. This cat will be looked after.

And the vet said nothing about a "hard, biggish abdomen"? That's what had me concerned.
A cat that had kittens weeks before wouldn't have such an abdomen.

I took my cats in to the vet the day after I found them. I think the older cat was between one and one and a half years old when I found her. The other cat (her daughter?) was between six and ten months old. The vet looked for spay scars, did blood work to check for nasties, etc. I'm the one who mentioned my fears of pregnancy- vet felt around, noticed the enlarged teats but felt it could be from nursing the six month old (!), who made no attempts to nurse at all during this initial time I found the two. So, it's easy for this sort of thing to fly under the radar, especially if the vet is a dim-bulb, as mine was. My vet couldn't explain what the firm belly was about (these cats were otherwise very thin) and did take an x-ray, from which she determined the cat was not pregnant. To cut the vet a break, I imagine it was possible that the bones of the fetuses were not calcified enough to show up on an x-ray- it was a shock to find out she was pregnant two weeks later.

Thanks for clarifying!

I think you need to take her back to the vet.

I adopted a cat a few years ago and she had a huge pregnant belly. I was sure she was pregnant, and so was the vet, initially, until he did an extensive examination and determined she had a huge wormy belly. Worm meds took care of it.

Your situation is, of course, different, but you still could use a vet visit. Lucky kitty to have you in her life!!

I got all caught up in kitty pregnancy and forgot to congratulate you on your new cat! Congrats...she's going to have a good home.

Even if your cat is pregnant, you can still have her spayed. It generally isn't any more than having her spayed while she's in heat. If you have issues with spaying a pregnant cat, I don't have much advice for you. There are plenty of kittens needing homes, along with plenty of non-kittens getting euthanized every day here in the USA. You can easily spay a cat while pregnant, but if it's an issue for you, please at least place the kittens through a local shelter with some sort of criteria for prospective owners.