If you have a standing appointment, you probably do need to let her know you are taking a break for couple of months and that you'll get back to her when you are ready to return. I don't know that you have to explain why you are taking a break, but it would be courteous to let her know she has that time slot open for other clients if she needs it.

I never had standing appointments, so when I took a break I just took a break. No explanation necessary. I called back when I was ready to return and made an appointment.