Is antenatal steroid treatment effective in preterm IUGR fetuses?

There are no randomized studies on the effect of antenatal corticosteroids in preterm intrauterine growth restricted (IUGR) fetuses. Fetal lung maturation has been postulated to be enhanced in these fetuses, which may result in little benefit of steroid treatment. Furthermore, corticosteroid treatment may be detrimental, as has been shown in IUGR animal models. The objective of this study was to review the available literature on antenatal steroid treatment of the IUGR fetus. All available reports on antenatal steroid treatment of IUGR and small for gestational age (SGA) fetuses published prior to October 2007 were included in this review. IUGR fetuses are a subgroup of SGA fetuses that are small due to placental insufficiency, which is reflected in abnormal Doppler examination of the umbilical artery. The main outcome measures were respiratory distress syndrome (RDS), intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), and neonatal mortality. No difference in neonatal mortality was seen in any of the reviewed studies and RDS, IVH, and NEC incidence did not differ between treated and untreated IUGR fetuses. In SGA fetuses, results on RDS incidence and intracranial outcome were inconclusive. Antenatal steroid treatment does not seem to have an effect on neonatal mortality or morbidity in IUGR fetuses. In SGA fetuses, it remains unclear if antenatal steroid treatment is beneficial due to heterogeneous populations and treatment regimes. A randomized controlled trial should be performed to confirm prior results and answer further questions regarding antenatal steroid treatment of these fetuses.