From a scientific technical point of view, miscarriages are also called “abortions”, though they usually are called spontaneous as well. That the tissue came from a miscarriage can’t be ruled out because of the language in the paper.
I’d wait to hear exactly what Carson says about it now that this has come to light. He may not have been pro-life at that point. I’m going to wait before I pass judgment on him.
Aborted - in text like that - could mean via induced abortion (like what PP did) or natural abortion (when the baby dies in the womb on its own).
Don’t assume.