J.B.
I agree with Cate...same thing, different delivery. How often would the shots be and are you good with needles? Progesterone shots are pretty nasty - the needle is large (both long and thick), the stuff is in a very thick oil that takes a little time and effort to push in and you have to take the shots in the thigh or hip. It's a bit of a production, and it hurts. If it's daily, I would take a pill.
Congrats on your good tests - you must be relieved!