A Lithopedion or a stone baby, is a rare phenomenon which occurs most commonly when a fetus dies during an abdominal pregnancy and the dead fetus isn't expelled or is too big to be reabsorbed by the body, and calcifies on the outside as part of the degenerating remains like a foreign object to prevent any further damage. Even when it occurs, the calcified remains usually unnoticed. In some cases, women have carried these remains in their body for over 50 years.

Lithopedion is usually detected when investigating abdominal pains and irregular bleeding, or as an accidental finding that require being subjected to an X-ray study. Lithopedion occurs only when the fetus has developed for 14 weeks or more. According to one report there are only 300 known cases of Lithopedia in the world, recorded in over 400 years of medical literature. Rare cases occurs like in 2013, a 75- year old Moroccan woman gave birth to a 'stone baby' that she conceived 46 years earlier and had carried inside her for nearly half a century. Similarly, in 2015, 91-year old Chilean woman named Estela Melendez was given the news of having a stone baby in her womb by doctors after an X-ray following a fall.

Lithopedion occurs in those scarce instances where proper medical aid isn't available to women and is often seen as the result of negligence. However, even in the case of lithopedion formation, woman have been known to give birth to other children normally.

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