I have used and recommend Laura Allen of Laura Allen Studios. She doesn't have a studio but rather comes to your home or other off-site location such as the beach, park, yard, etc and sets up everything for high quality shots. We've done our engagement photos, family/group shots, our dogs and cats!, baby photos and now will have her come again for our newest baby of 7 weeks. We love her and the photos. We never did maternity, but I have seen some and they are beautiful. She has a website www.lauraallenstudios.com
I generally use JCPenny, Sadies or Picture People for quick, cheap shots throughout the year....sometimes only taking home the free 8x10 for a timeline for her baby book.....but for real good professional shots we use Laura every couple years.
Good luck!