“Making the decision to have a child is momentous. It is to decide forever to have your heart go walking round outside your body.”
So the much-shared saying from Elizabeth Stone goes, and there is actually a lot more truth in it than we may have ever realised.
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While many mums describe their children as having a piece of their hearts, scientific research has found that this is much more than just a metaphor.
A phenomenon called microchimerism that occurs during pregnancy means that unique genetic cells are transferred between mother and child.
In the womb, DNA cells from the child’s heart, liver and other organs cross through the placenta and into the mother’s blood. These cells colonise the mother’s body and can be found anywhere from the brain to the skin and the heart.
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In return, cells from the mother travel through the placenta and into the baby’s body, living on in the lungs, spleen, kidneys and more.
“Making the decision to have a child is momentous. It is to decide forever to have your heart go walking round outside your body.”
Elizabeth Stone
While some of these cells may only stay for some time, others have been found to stay forever, providing extraordinary scientific evidence of the incredible bond between mother and child.
What’s more, because this process repeats with each pregnancy, younger siblings may receive some of their older sibling’s DNA, meaning they carry a mix of both their mother’s and their sibling’s DNA.
Research is yet to determine the evolutionary benefits of microchimerism, but one study,* which compared the phenomenon in mice to humans, presented the theory that it has developed “as a mechanism by which the foetus ensures maternal fitness”. By which it means that the shared cells may help with healing wounds and building a stronger immune system to ensure the mother is strong and well enough to grow and support a fit and healthy baby.
While some of these cells will leave the mother’s body soon after giving birth, others can remain much longer. One study found male cells in maternal blood even decades after pregnancy, “including in one case in which the woman was last pregnant with a male child 27 years later,” a report on Cell Migration from Baby to Mother reveals.
The report adds: “Male cells were also detected in all bone marrow samples from women who had previously been pregnant with males, including one woman who was last pregnant with a son 51 years earlier.”
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Remarkably, fetal cells have been detected in a mother’s blood as little as four weeks and five days after conception, while both fetal cells and DNA are consistently detected after seven weeks.
It may offer some comfort to any mums who have experienced baby loss, as it proves our children are always with us, even if we aren’t lucky enough to hold them in our arms.
Microchimerism is a topic Myleene Klass recently touched upon during an appearance on Mother Pukka’s podcast. Reflecting on her own miscarriage, Myleene was moved to tears as she explained: “They never leave you. The DNA stays in your body so they never really leave you.”
How wonderful is that?
References:
* Cell Migration from Baby to Mother, Gavin S Dawe, Xiao Wei Tan, and Zhi-Cheng Xiao,