Effect of Parity on Fetal and Maternal Microchimerism Interaction of Grafts Within a Host?

When an individual harbors small amount of cells or DNA from another person, it is referred to as microchimerism (Mc). During pregnancy, Mc occurs naturally as the result of trafficking of cells both from the mother to the fetus and from the fetus to the mother. Maternal Mc (MMc) is the situation in which an individual carries cells from his or her own mother, which he or she acquired as a fetus. The reverse situation is fetal Mc (FMc), which occurs when fetal cells enter the maternal circulation during pregnancy. Both MMc and FMc can persist for years as “graft” cells. Thus a pregnant woman may harbor cells both from her own mother (which she acquired as a fetus) and from her offspring (which she acquired during pregnancy). Although multiparous women would be expected to acquire new sources of FMc during each gestation, and thus to display more FMc as compared with those who have had only a single pregnancy, the effect of multiparity on Mc is not completely known.