Infection and preterm birth: Evidence of a common causal relationship with bronchopulmonary dysplasia and cerebral palsy

Subclinical genital tract infection has been clearly established as a significant cause of spontaneous preterm birth, particularly in early gestations. Bacterial vaginosis organisms rank highly among the pathogens involved in preterm labour and there is considerable beneficial evidence from the use of prophylactic antibiotics for women at high risk of preterm birth. The pathogenesis involves activation of macrophages and the generation of pro-inflammatory cytokines. Bronchopulmonary dysplasia is seen in the most immature of survivors and appears to be secondary to interruption of normal development and maturation of the lungs. The link between chorioamnionitis and lung injury in utero, and subsequent development of bronchopulmonary dysplasia has now been substantiated. Exposure to pro-inflammatory cytokines is implicated in the impairment of the fetal lung. A significant body of evidence supports the association between chorioamnionitis, periventricular leukomalacia and cerebral palsy. Biological mechanisms that explain the association between chorioamnionitis and fetal brain injury involve pro-inflammatory cytokines. Similarity in the pattern of expression of cytokines suggests a common pathway for the initiation of preterm labour and also injury to the lung and the central nervous system of the fetus.