Testing for risk of preterm delivery.

Four discrete mechanisms for the pathogenesis of PTD have been described but they share a final common pathway. Moreover, although the mechanisms have distinct clinical characteristics, they are not mutually exclusive. As an example, triplet gestations are more likely to be associated with periconceptional intrauterine manipulations predisposing to infection, as well as fetal growth restriction, decidual hemorrhage, and pathologic uterine distention. An improved understanding of these pathologic pathways has led to the development of new tests to predict PTD. Use of multiple markers (eg, serum CRH, salivary E3, cervical IL-6, TAT, and fFN) holds promise for implementing targeted interventions to prevent PTD.