I love fall and Halloween and my favorite part of both has to be pumpkins. I love carving them, painting them and cooking with them. Real pumpkins can be a great prop. When I am working with a baby, I often will just cut the top off the pumpkin and sit the baby right inside. I usually line the inside of the pumpkin with a rag or towel to keep the baby's from touch the slimy insides and crying.
If the baby you are working with is a little bit bigger, you can cut leg holes in the pumpkin to give their little legs some place to go. My advice with leg holes is cut the bigger than you think they are going to need to be.
If you prefer not to stick a baby inside of a pumpkin, you can always use the pumpkin as a prop to lean against. Anyway you use it, the pumpkin is the perfect prop for October.