If she's getting enough bm/formula, I'd agree with Melissa and say that her body is probably adjusting. I know I was paranoid the first time ds went without a bm for more than a day, but it was completely unwarranted. Babies can go for several days w/o a bm.
The pears suggestion is a great idea. It will guarantee to 'move' things along, even if there were no problem. Also, oatmeal is a great idea. It's definitely good for the digestive system and, I personally believe, better than rice cereal.