The phenomenon has only occurred a handful of times, with about three hundred known cases ranging back in time.
Lithopedions are thought to form following pregnancies in which the fetus actually grows outside of the mother’s uterus. And, if the fetus grows too large, it cannot be reabsorbed by the body.
So, it instead passes away unborn and can actually stay within an expectant mother’s body forever.
When Colombe’s lithopedion was discovered during the sixteenth century, though, it was unlike anything anyone had ever seen or heard of. And the “stone baby” intrigued ordinary community members and medical experts alike– ultimately getting passed around and studied over the following few hundred years.
And since the Sens lithopedion was discovered, forty-six additional cases of “stone babies” were documented within medical studies. Plus, over time, medical professionals came to conclude that lithopedions formed under three different circumstances.
First, the surrounding egg-shaped membrane could calcify while the fetus inside does not. Second, the hard membrane shell could rupture and cause the fetus to calcify. Or finally, both the membrane and fetus could calcify independently of each other– like Colombe’s baby.
And because these “stone babies” were never born, it was rare to discover a lithopedion until their mothers reached the end of their lives. In fact, a 1949 case study actually revealed that of the one hundred and twenty-eight documented cases of lithopedions, nine of the mothers spent over fifty years unknowingly carrying the “stone babies” within their abdomens.
Still, lithopedions are extremely rare. Cases of abdominal pregnancy– in which the baby grows outside the fallopian tubes or uterus– only represent one out of every ten to thirty thousand pregnancies. Then, calcification that results in a lithopedion represents less than two percent of those cases.
And nowadays, with advancements in medical technology and prenatal care, the odds of living with a lithopedion inside of you are incredibly low.
Abdominal pregnancies alone are already known to pose distinct risks to both mother and baby– so oftentimes, these pregnancies are terminated early on.
Additionally, the pregnancies that are not terminated are watched closely by medical professionals– and any abdominal fetus that does not survive is promptly removed before calcification can occur.