Being Close To Your Mother

Andrew Sullivan —  Sep 12 2011 @ 9:51am

Sometimes, a little too close. A mother can carry cells from her fetus for years after the pregnancy ends. Chris Gunter explains the science behind fetal microchimerism:

Particularly in the last two decades, microchimerism has been recognized as the norm rather than the exception. We now know that, instead of being separate systems, the mother and fetus leave a number of permanent marks on each other through the trafficking of cells back and forth over the placenta. Fetal stem cells make their way into the mother’s bloodstream and even into her bone marrow, sometimes contributing to her blood supply for the rest of her life. …

But the presence of fetal cells is also invoked as the reason why women have more autoimmune disorders, including lupus and thyroiditis, during and years after pregnancy. Immunologists think that this happens essentially because Mom’s immune system eventually realizes that these fetal cells don’t belong to her own body, and attacks them as a result.