Beverly Muzuki, a 20-year-old gravida 2, para 0, 30-week pregnant woman, noticed some mild lower abdominal pain but thought it was irritation from a bladder infection and waited to get help until she went to her scheduled appointment at the hospital. During the night, she woke up twice because of a nagging lower backache. This morning, she has intermittent sharp uterine contractions. “Why am I starting labor so early?” she asks you. “Is it because I’m Rh negative?”