I've always preferred L'Heureux's short fiction to his novels, but perhaps this will even out the score. His story, "The Comedian" is a haunting, funny story about a female comedian pregnant with a child who won't stop singing in utero. It's insidious a pro-life story as you'll ever find.
Speaking of subtly, perhaps even reluctantly prolife fiction, check out the first story in the Best Short Stories of 2002. It's "Along the Frontage Road" by Michael Chabon. Even if you don't want to buy the book, you can sit in the bookstore cafe and read this story. There's a sad truth at the heart of it.
And speaking of writing about abortion in short form, although it's not fiction (sadly) don't forget the chapter on "Abortion" in Richard Selzer's Mortal Lessons. Give it to someone you know who's on the fence, and see if they don't fall right off.