Fetal cells transfer to the mother during pregnancy and can persist long-term as microchimerism. Acquisition of microchimerism may also occur during pregnancy loss, either miscarriage or pregnancy termination. Because nearly half of all pregnancies end in loss, we recently investigated the magnitude of fetal cell transfer during pregnancy loss and whether obstetric clinical factors impacted cell transfer. Prospective measurement of fetal cellular microchimerism before and after miscarriage and termination of pregnancy demonstrated a significant transfer of fetal cells in these pregnancies, with higher concentrations of fetal microchimerism in pregnancy termination vs. miscarriage and in those that were managed surgically vs. medically. The frequency of pregnancy loss as a proportion of all pregnancies, and the overrepresentation of fetal genetic abnormalities in pregnancy loss suggest that the resultant acquisition of fetal microchimerism could have a unique and substantial impact on women's health.