I've always assumed the Doctor is. He always comes across as someone who values life and doesn't tolerate pointless killing. But with Capaldi's Doctor I'm not so sure. In Mummy on the Orient Express he showed a somewhat brutal and uncaring side to him, and although it goes with an explanation, it still opens the question to debate. Also, on kill the moon he left the decision to others, the fate of a species to normal people.
Kill the moon was awful. I think either Flatline or Dark water are my favorite so far. And I'm confused as to your answer, do you mean Peter Capaldi the actor is Pro-Life or do you mean the doctor?