A stone baby, or lithopedion, results when a foetus dies during an ectopic (typically abdominal) pregnancy, is too large to be reabsorbed by the body, and calcifies. 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 94 year old woman, whose lithopedion had probably been present for over 60 years.

Stone babies are rare, occurring in only 0.0045 percent (1 in 22,000) of pregnancies. Fewer than 300 cases have been noted in medical literature accumulated over some 400 years. Lithopedion may occur from 14 weeks' gestation to full term.

The earliest stone baby is one found in an archaeological excavation, dated to 1100 BC. The condition was first described in a treatise by the great physician Albucasis in the 10th century AD.

A related condition is known as foetus papyraceus, in which the foetus is one of two or more sharing the womb. If the foetus is older than eight weeks at the time of its death, and is retained in the uterus for at least ten weeks, it may undergo mechanical compression such that it takes on a flattened, mummified appearance and resembles parchment paper.

External links

• OBGYN.Net
  
• PubMed (enter 'lithopedion' in search box)