Transplacental versus direct fetal corticosteroid treatment for accelerating fetal lung maturation where there is a risk of preterm birth.

backgroundDespite major advances in medical technology, the incidence of preterm birth remains high. The use of antenatal corticosteroid administered transplacentally, by intramuscular injection to women at risk of preterm birth, has reduced the incidence of respiratory distress syndrome and increased the survival rates of preterm infants. However, this intervention also comes with its own risks and side effects. Animal studies and early studies in pregnant women at risk of preterm birth have reported the use of an alternative route of administration, by direct intramuscular injection of corticosteroid into the fetus under ultrasound guidance, in an attempt to minimise the side-effect profile. Direct fetal corticosteroid administration may have benefits over maternal administration in terms of safety and efficacy.

objectivesTo assess if different routes of corticosteroid administration (maternal versus direct fetal) have effects on health outcomes for women and their babies. SEARCH

methodsWe searched the Cochrane Pregnancy and Childbirth Group's Trials Register (25 October 2017), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (25 October 2017) and reference lists of retrieved studies. SELECTION CRITERIA: Randomised controlled trials comparing maternal with direct fetal routes of antenatal corticosteroid administration in women at risk of preterm birth. DATA COLLECTION AND ANALYSIS: The two review authors independently assessed study eligibility. In future updates of this review, at least two review authors will extract data and assess the risks of bias in included studies. We will also assess the quality of the evidence using the GRADE approach. MAIN

resultsWe did not identify any eligible randomised controlled trials to include in this review. AUTHORS'

conclusionsThe available clinical studies carried out so far on animals and human have shown that direct intramuscular injection of corticosteroid into the fetus under ultrasound guidance is feasible, but data on health outcomes are lacking. Uncertainty therefore persists as to which method could provide better efficacy and safety. Randomised controlled trials are required focusing on the benefits and harms of transplacental versus direct fetal corticosteroid treatment. Until the uncertainties have been addressed, it is advisable to stay with the current standard of antenatal transplacental maternally-administered corticosteroid treatment.