Prevention of preterm birth.

Preterm labour and delivery remain a major cause of perinatal morbidity, mortality and long-term adverse neurodevelopmental outcome. An effective primary prevention strategy is desirable, but current approaches appear largely ineffective at present. Understanding the aetiology of the onset of preterm labour continues to improve with the recognition of the role played by subclinical infection in a significant proportion of cases. The investigation of hormonal influences in the aetiology of preterm labour is at an early stage, but there appears to be a relationship between raised serum relaxin concentrations and preterm delivery (Petersen et al, 1992). The naturally occurring phospholipase A2-inhibitor gravidin, believed to be important in pregnancy maintenance, is found in a reduced concentration in women delivering preterm (Wilson, 1993). The relationship between hormonal levels, socio-economic influences, subclinical infection and actual preterm labour and delivery remains to be established. Secondary prevention with tocolysis remains unsatisfactory, owing to the low therapeutic index of currently available agents and their varied maternal and neonatal adverse effects. The investigation of newer tocolytic agents remains a worthwhile pursuit, whilst the underlying aetiology of preterm labour and effective prevention remains to be elucidated. The widespread recognition of the benefits of antenatal corticosteroid administration and subsequent adoption into clinical practice has reduced, and will continue to reduce, the morbidity associated with preterm birth while newer methods of accelerating fetal maturation are explored and applied in clinical practice.