Can obstetric care provide further improvement in the outcome of preterm infants?
Reducing the incidence of cerebral damage in preterm infants has become a major objective of perinatal medicine. Recent studies have shown that intrapartum hypoxia is implicated in only 10% of cases, whereas prenatal factors are significantly linked with such damage. The main risk factors associated with cerebral palsy are preterm birth, multiple pregnancy, intrauterine infection, serious hypoxaemic and haemodynamic disorders and, possibly, thrombophilic disorders. Recent progress in recognition of the pathogenesis of cerebral white matter damage has underlined the roles of cytokines, including interleukins 1 and 6 and tumour necrosis factor alpha (TNFalpha), and of a massive release of glutamate, which leads to the excitotoxic cascade. Three measures have had demonstrable benefits in improving neonatal outcome in preterm infants: a policy of prenatal transfers to tertiary level care units, antenatal corticosteroid therapy, and administration of antibiotics to women with preterm premature rupture of membranes. The influence of tocolysis is usually considered to be relatively minor, but further studies in very preterm pregnancies may be required. The recent development of tocolytics without major adverse effects will probably facilitate such studies. The mode of delivery of early preterm infants is another important area of controversy. Recent studies have suggested that a policy of elective caesarean section in PPROM and in the case of breech presentation of fetuses weighing less than 1000-1500 g would be beneficial. Lastly, in vitro and animal studies have shown that several pharmacological agents can prevent white matter disease by interacting with cytokine and the excitotoxic cascade. This will probably constitute an important area of research in the future.