Maternity pictures at extended family shoot

Hello! I booked a family photo shoot with a photographer as a mothers day gift for my mother! After booking the photo shoot I learned that both my sisters are pregnant! I am sure they are going to want a few pictures of just them and their partners. One wants a photo with a “big brother” bid on her dog. I am ok with this. My question is will the photographer be ok with this? Should i reach out to her prior and let her know and ask if we need to pay extra for this? I booked and paid for a 45 minute shoot! All input is appreciated! Thanks