Matt Laur , Jan 12, 2010; 01:42 p.m.
Do you expect that she has in mind any use for these images beyond simply displaying in her home, or giving them to relatives? If she's a potential stage mom, or will be using these for her child's modeling portfolio, etc., you need to think of the paperwork as being a two-way street. You definitely want her to sign a contract in advance, and it should clearly state if/when/how she can reproduce or othewise use your the images (to which you will own the copyrights), as well as clearly define what she'll get out of your work, and for how much.
Follow-up, additional prints or other media can come as a separate order, and with their own language.
You have to decide if you want to get granular about this and charge for your time as well as for delivered prints, or go for a more "package" approach. Since it doesn't sound like you've got a finished bundle of goods in mind, consider a sitting fee ($150?) that includes online viewing of proof material. Then treet the prints as separate business.