I shoot my moms between weeks 32 and 37 so they're the most comfortable. Those last 2-3 weeks of pregnancy S U C K. Ankles start to swell, BH CTX come on, it's just a general suckfest of uncomfortableness. I shoot all natural light, mostly outdoor sessions, but if a mom wants I will come to their home and take some photos of her (and siblings) in the home, in the nursery etc. I like my moms to have a couple outfits ready- something form fitting to really show off that bump; knits are good for this and then something softer and more flowing. I do NOT use maternity gowns- I don't shoot moms in their underpants. Make sure the mom can take breaks especially if you're nearer the 36-38w mark. Make sure to remind her to bring lots of water along- or have water handy for her. Like everything else photography related, you need to find what works for you with regard to style. Are you looking for someone to take your photos or are you taking photos for someone else?