Can a fetus send its own stem cells to repair its mother’s damaged organs?

When the mother suffers organ damage during pregnancy, the baby in the womb sends stem cells to repair the damaged organ.
A popular (but entirely uncitational) science meme suggests that a pregnant mother’s fetus can send its own stem cells to its mother to repair damaged organs. While all memes of this type span the gamut from “nodding, acquainted with the truth” to “never met the truth and never will,” this particular one is mostly accurate.
While the meme’s wording is problematic for two reasons (first, the meme’s text generally says “baby,” which is incorrect since that term implies birth; second, the wording implies a conscious decision on the part of the fetus to send its tissue as heroic gesture), the science behind the claim is actually pretty solid.
The transfer and incorporation of fetal stem cells into a mother’s organs is known as fetomaternal microchimerism. A 2016 article in the Journal of Cancer Research and Clinical Oncology defines the phenomenon so:
Fetal cell microchimerism is defined as the persistence of fetal cells in the mother for decades after pregnancy without apparent rejection. Fetal microchimeric cells (fmcs) implant in the maternal bone marrow and are able to migrate through the circulation and reach tissues.
stem cells are essentially blank slates that can transform into a variety of different tissues and as such play a huge role in the development of a fetus. The idea behind fetomaternal chimerism is that despite the cells’ distinctly different genetics, these cells can be transported out of the fetal system and fully integrated into the mother’s system.
Scientists have known (broadly) the existence of fetomaternal microchimerism for decades. A 1996 learn in Proceedings of the National Academy of Sciences, for example, found that in humans, genetically distinct cells from a male fetus persisted in the mother’s body for up to 27 years after birth.
Later Research has shown that these fetal cells can be found in several organs in both human and laboratory mouse mothers:
Fetomaternal transmission is likely to occur in all pregnancies, and in humans, fetal cells can persist for decades. Microchimeric fetal cells are found in a variety of maternal tissues and organs, including blood, bone marrow, skin, and liver.
A 2015 Study published in the journal circular research addressed the question of whether fetal stem cells actually heal maternal organs. In this study, the researchers paired female mice with transgenic male mice tagged with a fluorescent protein that allowed the researchers to track the flow of fetal stem cells from the mother’s placenta into her heart while she was with the mother caused heart injury. They found that fetal stem cells directly targeted the damaged heart cells and fully integrated into the mother’s heart. This research, the authors explain:
Indicates the presence of precise signals perceived by cells of fetal origin that allow them to specifically attack diseased myocardium and differentiate into different cardiac lineages. Most notable is their differentiation into functional cardiomyocytes capable of beating in syncytium with neighboring cardiomyocytes, possibly unveiling an evolutionary mechanism by which the fetus helps protect the mother’s heart during and after pregnancy.
While this study was done in mice, there is one wide body of research suggesting that similar phenomena could occur in humans. However, there is still much research to be done regarding the overall mechanisms behind this process and the full range of effects it can have on both the fetus and the mother.