How can you tell if your Chinchilla is Pregnant?

I've recently noticed weight gain, strange behavior and I'm pretty sure large teats, as I've been researching - that is one of the main tell, tell signs. Although, I've only seen one once and this is before I read that you probably shouldn't be handling your chin if she is pregnant.. as I don't want to disturb her or potentially hurt kits.. Are there any other signs?

(She has joint play time with one of my male Chinchillas)