I'm of the opinion that if it's not viable outside of the human host, then it's medical waste.
If for whatever reason the mother wants to keep a fetus for burial purposes, or if someone wants to keep their amputated leg in a case on their mantle, then there could be a process for that, but the decision to offer that service would be up to the hospital. There are some serious safety concerns when it comes to how these things are handled. The safest is to discard and incinerate.
Now when you incinerate, you can let that energy go to waste, or you can use that energy to help offset electricity/gas bills. Personally, I think the socially responsible thing to do when incinerating, if you have the option, would be to convert it to energy/heating.