It's called "lithofacia," which literally means "stone baby."

This condition usually occurs during an abdominal pregnancy (an ectopic pregnancy in which the embryo implants in the abdomen): when the fetus dies, if it is too large or too old, the mother's body cannot fully absorb it. At this point, the dead fetus will gradually rot, which may cause severe sepsis and even endanger the mother's life. The human body will activate a protective mechanism called "foreign body reaction" - guiding calcium salts to accumulate around the fetal remains and completely wrap them up to isolate the risk of infection.

Lithofetal disease is extremely rare: only about 300 cases have been recorded worldwide in 400 years of medical literature. It should be noted that the incidence of abdominal pregnancy itself is only 1 in 11,000, and only 1.5%-1.8% of these will develop into lithofetal disease. It is worth noting that because the stone fetus is located outside the reproductive system and has lost its activity, the mother may still have normal pregnancies and other children later, as long as the damage caused by the ectopic pregnancy is completely healed.