From what I understand, taking progesterone orally isn't as effective because it is mostly destroyed by the acids in the stomach and also the liver. It's better to apply it topically on thinner-skinned areas. If you were given oral progesterone, you could potentially break the capsules/tabs and mix it with a regular lotion.
I personally used natural progesterone cream while on spiro for a while and had no problems. It relieved some estrogen dominance symptoms that were caused by spiro but my goal was to get off spiro all together.