Pictocin for placenta?

Au
Im planning an all natural birth in a hospital. We will be doing hep lock as required by my hospital, but no medications. 
I just found out today that it's standard practice at my hospital to give pictocin for delivering the placenta and helping the uterus contract back. This doesn't bother me a great deal, as it won't be affecting baby, but I still was caught off guard by this news. What are your thoughts on this? I kind of would prefer not to, but need to discuss with my dr as well.