Nanny pay question- opinions needed! Read below

We have a nanny to care for my now one year old son during the school year (I have summers off). She cared for him last school year, and is now returning in the fall for this next school year.

When we first hired her I had originally thought about giving her a raise each year that she returned. (I never discussed that with her, I just thought it would be a nice idea).

When she returns this fall she is bringing her four-month-old baby with her and will care for her baby and my toddler at the same time. In the past I had thought that if a nanny wanted to bring their children with I would negotiate a slightly lower rate since their attention is split and they are saving a ton of money by bringing their child to work.

What I'm wondering is if I should still give her the yearly raise when she returns in the fall, or if her bringing her daughter with levels that out? (I definitely wouldn't pay her any less than she made last year!) She works about 25-30hrs per week if that matters.

She is obviously our first nanny so I'm not really sure how this typically works...

What are your guys thoughts?