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Corticosteroids for Foetal Maturation

NIH consensus conference

The use of antenatal corticosteroids for foetal maturation in preterm infants has been carried before in Bandolier in relation to a GRiP project in Oxfordshire ( Bandolier #2 , March 1994). The report on the NIH consensus conference on this subject has just been reported in JAMA [1]; while the conclusions are not different, this will be useful information for those engaged in the practice of evidence-based medicine.

The conference asked and sought to answer seven questions, and, as usual for NIH consensus conferences, did the job thoroughly. This was important for the USA, where only 15% of the 106,000 babies born weighing less than 2,000 grams are treated with corticosteroids. Though judging the economic consequences of treatment are difficult, the conference estimated that cost savings of about $3,000 would result from each treated neonate, and increasing the proportion treated from 15% to 60% would result in savings of about £160 million in the USA.

The conference made a number of recommendations for the use of antenatal steroids, and these are shown in the box.


NIH recommendations for the use of antenatal corticosteroids

  • The benefits of antenatal administration of corticosteroids to foetuses at risk of preterm delivery vastly outweigh the potential risks. These benefits include not only a reduction in the risk of respiratory distress syndrome (RDS) but also a substantial reduction in mortality and intraventricular haemorrhage (IVH).
  • All foetuses between 24 and 34 weeks gestation at risk of preterm delivery should be considered candidates for antenatal treatment with corticosteroids.
  • The decision to use antenatal corticosteroids should not be altered by foetal race or gender or by availability of surfactant replacement therapy.
  • Patients eligible for therapy with tocolytics should also be eligible for treatment with antenatal corticosteroids.
  • Treatment consists of two doses of 12 mg of betamethasone given intramuscularly 24 hours apart or four doses of 6 mg of dexamethasone given intramuscularly 12 hours apart. Optimal benefit begins 24 hours after initiation of therapy and lasts seven days.
  • Because treatment with corticosteroids for less than 24 hours is still associated with significant reductions in infant mortality, RDS and IVH, antenatal corticosteroids should be given unless immediate delivery is anticipated.
  • In preterm premature rupture of membranes at less than 30 to 32 weeks gestation in the absence of clinical chorioamnionitis, antenatal corticosteroid use is recommended because of the high risk of IVH at these early gestational ages.
  • In complicated pregnancies where delivery before 34 weeks gestation is likely, antenatal corticosteroid use is recommended unless there is evidence that corticosteroids will have an adverse effect on the mother or delivery is imminent.

The Grand Canyon

It is obviously extremely important for the NIH to have had a consensus conference on steroids and foetal maturation, but one has to ask, perhaps, why it has taken so long, even though it is a welcome addition to the movement for evidence-based medicine.

The first RCT on the effects of giving a short course of corticosteroids to women expecting to give birth prematurely was reported in 1972. The Cochrane Collaboration logo summarises the evidence that would have been revealed had a systematic review of available RCTs been performed a decade later in 1982. Those who have seen the logo will notice a diamond lying to the left of a vertical line which indicates no effect; this marks that the result produced significant benefit when the results of seven trials were combined.

The reality was that it was 1989 that a systematic review of the RCTs had been prepared and published, but the problem seems to be that uptake of knowledge is very slow.

British grand canyon

There always seems to be a yawning gap between the knowledge that is available and the implementation of that knowledge. This can be seen in the UK as well as the USA.

Even when the knowledge on corticosteroids is available as beautifully as it is on the Oxford Database of Perinatal Trials produced by the Cochrane Collaboration, it seems not to be available where it is needed, as a survey of obstetric units in England has shown [2]. Sara Paterson-Brown and her colleagues conducted a telephone survey of all 24 teaching hospitals and 74 of 173 district hospitals in England to about knowledge and implementation of the Database.

The results are shown in the table above. The Database was unavailable in 38% of the teaching hospitals and 84% of the district hospitals. The number of hospitals which used it to formulate policy through protocol design or to handle specific patient problems was disappointingly small.

Perhaps things have changed since 1993.

References:

  1. Effect of corticosteroids for fetal maturation on perinatal outcomes. Journal of the American Medical Association 1995 273: 413-8.
  2. S Paterson-Brown, JC Wyatt, NM Fisk. Are clinicians interested in up to date reviews of effective care? British Medical Journal 1993 307: 1464.



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