To tell this story is to tell its end first. On Sept. 1, 2012, Makenna, the only child of Heather Thompson and Geoff Duff of Alexandria, Va., was born dead. She had been alive in her mother’s womb on Aug. 30, but no heartbeat could be found the next day. Her umbilical cord had knotted, then wrapped around her neck, and, at 39 weeks, she was stillborn. Until her baby’s heartbeat could not be found, Thompson says, the pregnancy had been medically uneventful.