Introduction

Since the third edition, this chapter has been expanded to cover both polycythemia and fetomaternal hemorrhage, a topic that is not extensively or comprehensively discussed in most commonly used textbooks. In the former the hematocrit and blood volume are generally increased, while in the latter both are generally very low. In both conditions, however, there is concern about inadequate organ blood flow, oxygenation delivery, and potential for hypoxic injury, especially in the brain. A large body of definitive information on polycythemia is available that allows conclusions to be made as to management and patient outcome. However, the area of fetomaternal hemorrhage has not been as comprehensively investigated and relies mostly on small clinical series and case reports. There are no controlled basic or clinical trials, which hampers our understanding of pathophysiology as well as therapeutic modalities. This leaves us with gaps in our knowledge of this important topic. What is presented here is the most current body of information and recommendations for diagnosis, treatment, and reported outcomes.

Polycythemia

Polycythemia and hyperviscosity were first associated with adverse neurologic events and sequelae in a series of case reports. The first case often referenced was published by Wood in 1952, and this was followed by a small series of infants with polycythemia and hyperviscosity who displayed multiple problems, including cerebral dysfunction.