1. Half-dose antenatal betamethasone did not meet the noninferiority criteria when compared to full dose at preventing the primary outcome of neonatal surfactant usage.
2. There were no differences in neonatal death and adverse events between the half-dose and full dose groups.
Evidence Rating Level: 1 (Excellent)
Study Rundown: Antenatal betamethasone is standardly given prior to preterm delivery to accelerate fetal lung maturation. The typical dosage is given twice 24 hours apart. However, recent studies suggest that this dosage may have dose-related side effects. This study, BETADOSE, was a non-inferiority trial that assessed the impact of half-dose betamethasone compared to standard dose on the need for intratracheal surfactant within 48 hours of birth. Based on a predefined cut-off, the use of half-dose was unable to show noninferiority compared to full dose betamethasone. There were no differences seen in neonatal death and severe adverse events between the two groups. Limitations of this study include having surfactant usage as a proxy for neonatal respiratory outcomes, as this could differ between clinicians. Additionally, this study is unable to assess the long-term neonatal effects of half-dose antenatal steroids compared to standard dosage. Nevertheless, the results of this study do not support the reduction of antenatal betamethasone dosage.
In-Depth [randomized controlled trial]: BETADOSE was a double-blind, placebo-controlled, randomized control trial that enrolled pregnant women aged 18 years or older with a singleton fetus at risk of preterm delivery. Participants had already received an injective of betamethasone before 32 weeks gestation. Exclusion criteria included having received a full course of steroids, being cervically dilated greater than 4 cm, and having a multiple pregnancy. 3244 women were randomized 1:1 to either half-dose (n = 1620) or full-dose (n= 1624) betamethasone. The half-dose group received a placebo dose rather than a second dose of 11.4 mg betamethasone. The primary outcome was the need for intratracheal surfactant within 48 hours of birth. In the intention-to-treat analysis, the primary outcome was observed in 20% of the half-dose group compared to 17.5% of the full-dose group (risk difference 2.4%, 95% CI -0.3 to 5.2). Non-inferiority was defined prior as shown if the higher limit of the 95% CI was less than 4 percentage points. Thus, non-inferiority was not shown. There were no risk differences of neonatal death or severe adverse events (grade 3-4 intraventricular hemorrhage, stage >2 necrotizing enterocolitis, severe retinopathy of prematurity, or bronchopulmonary dysplasia) between the two groups.
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