Introduction Fetal microchimerism refers to the presence of a small number of fetal cells in the maternal body (O'Donoghue, 2008). During pregnancy, fetal cells such as fetal stem cells or immune cells can cross the placenta and enter the maternal circulation. These fetal cells can then migrate and integrate into various maternal tissues and organs (Bianchi et al., 2021). As a result, the mother may retain a small population of cells that originated from her fetus.
