A Lithopeion (Greek:litho = stone; pedion = child), or stone baby, is a rare phenomenon which occurs most commonly when a fetus dies during an ectopic pregnancy, is too large to be reabsorbed by the body, and calcifies on the outside, shielding the mother's body from the dead tissue of the baby and preventing infection. Lithopedia may occur from 14 weeks' gestation to full term. It is not unusual for a stone baby to remain undiagnosed for decades, and it is often not until a patient is examined for other conditions or a proper examination is conducted that includes an X-ray that a stone baby is found. The oldest reported case is that of a 76 year old woman, whose lithopedion had probably been present for 46 years.