Disorders of the fetomaternal unit: hematologic manifestations in the fetus and neonate.

Histoarchitectural characteristics of the human placenta place the fetus at a high risk of growth restriction, abnormal fetomaternal cell traffic, and vertical transmission of pathogens. These abnormalities of the fetomaternal unit are frequently associated with hematological abnormalities in the fetus/neonate and may be the first, most common, or the only clinical manifestations of these conditions. This article reviews the pathophysiology and characteristic hematological manifestations of these conditions in the fetus and the neonate.