Nakara Alston was leaving her boyfriend when she learned she was eight weeks pregnant. In desperation, she got an abortion at a Planned Parenthood clinic in Albany, N.Y., and moved with her two daughters into a homeless shelter. But something was clearly wrong. Several weeks after the procedure, she was still bleeding heavily and suffering from painful cramps. She took another home pregnancy test, and when it came back positive, the clinic staff assured her that they had seen the aborted fetus and there was nothing to worry about. It was only after she went to an emergency room that...