A philosophy of practice based on evidence is well established in perinatal medicine and several large randomised controlled trials, organised in the UK, have made an important contribution in this regard. However, it is important to realise that, despite the current imperative in relation to evidence based practice,1 many fundamental aspects of perinatal care have not been subjected to a randomised trial. In the UK setting up studies to address such issues has always been difficult as there is only limited infrastructure available to support the process. Furthermore, important changes during the past few years, both within the service and in the public’s perception of the Health Service and research, mean that previous approaches may no longer be sustainable.

During the past 20 years there has been a major improvement in the survival of preterm infants that is unlikely to be repeated. As a result the primary outcomes of future trials are likely to be based on either very small improvements in survival (requiring large numbers of infants), or improved morbidity …