voice change?

Kitty, female, about 2-3 years old, has a high-pitched meow. Yesterday she started meowing lower, deeper. It sounds like an average meow now, not a high-pitched one. She goes back and forth from high to low sessions over the span of the day. What's happening? Should I be worried?

I think I remember reading somewhere that a change in voice could be a sign of a number of things... I'd call your vet and see what he/she says. I hope everything is okay!