I have no idea but my first thought is how close are you to the PA border because we could use a great house cleaner!!
I think I'd start with a small raise, something like 10% or like $5 or $10 more than usual (for her total, not per hour if that's how she charges you). So if she typically charges $100, maybe give her $110.
I may be WAAAY off on what is customary though. DH usually deals with these things in our house.
Mom to a spirited, red-headed, former 28-weeker 10/2009 and a more mellow monkey 12/2013.