T.S.
Is she using them for #1 or #2? If it's #1, there are many circumstances where this is "normal" and her bladder may still be developing. OR she is such a heavy sleeper, she doesn't wake up. I worry about this with my 2 1/2 yr old son as he is a VERY heavy sleeper. (The boy falls out of bed and doesn't wake up!)
If she's going #2 in her pants/pull ups I would just make a phone call to the doctor to see if there is anything to be concerned about.