Maternity Shoot Questions

So, I have my first paid maternity shoot in a couple of weeks. The client's husband is currently deployed so he won't be present for the shoot which will be on location at a park, but her 18 month old daughter will be and she had mentioned she'd love to make the shoot more about her daughter becoming a sister than her becoming a second time mom. Any idea for some shots that would achieve this? Examples are great

some good examples in this thread. also poke around flickr, ive seen great examples on there as well.