The Collaborative International Dictionary of English v.0.48:
pro-lifer \pro-lif"er\, n. One who is opposed to voluntary abortion; one who is pro-life, especially an activist in the campaign to make abortion illegal. [PJC]WordNet (r) 3.0 (2006):
pro-lifer n 1: an advocate of full legal protection for embryos and fetuses; someone opposed to legalized induced abortion