Though people say that moms will always carry part of their child in their hearts, the truth is more scientific. Researcher Amy Boddy explains that genetic material transfers from a fetus to the mother while she is pregnant. This transfer, called fetal microchimerism, can result in babies' cells residing in the mother for years - in some cases, decades.
One reason, Boddy theorizes, is that the baby can access those resources after birth: the mother may be more likely to continue taking care of the baby once it is born, if those cells are present in her body. It could be a baby's involuntary protective strategy.
Many studies on fetal microchimerism suggest that the fetal cells might help fight certain diseases, such as Alzheimer's. There remains much to study, but fetal microchimerism is comforting emotionally as well as scientifically: part of the baby does indeed stay with the mother, even after miscarriages.
Click here for more about Boddy and other researchers' studies on fetal microchimerism.