BETAmethasone Dose Reduction: Non-Inferiority on the Neurocognitive Outcomes of Children Born Before 32 Weeks of Gestation

Overview

Maternal antenatal corticosteroid therapy is the last major advance in the antenatal management of fetuses to prevent neonatal complications associated with prematurity. Long-term neurological outcomes in infants exposed to antenatal steroids have been assessed in few cohorts and suggest that this therapy is able to prevent some neurodevelopmental impairments including cerebral palsy. While \>85% of neonates born very preterm in Europe have been exposed to antenatal betamethasone, Cochrane collaborative networks stated that trials of dosages comparing different regimens of commonly used corticosteroids are most urgently needed to avoid useless fetal exposure to excessive dosage of corticosteroids. * Because a half dosage was associated with maximal benefits on lung function in ewes, a randomized controlled trial (BETADOSE, NCT02897076) has been conducted to demonstrate that a 50% reduced betamethasone dose regimen is not inferior to a full dose to prevent respiratory distress syndrome in preterm neonates. BETADOSE trial demonstrated that half dose did not show noninferiority to full antenatal betamethasone dose regimen to prevent severe RDS in preterm neonates while other prematurity-associated complications, including those usually prevented by ACS, did not differ between the two groups. * Results of the 5-year BETANINO follow-up study of the BETADOSE neonates are needed before deciding whether reducing ACS dose is possible The main hypothesis of BETANINO is that half dose regimen of betamethasone is not inferior to full dose regimen of betamethasone to prevent neurodevelopmental impairments in these high-risk children born very preterm at 5 years of age.

Maternal antenatal corticosteroids (ACS) therapy is considered to be the last major advance in the antenatal management of fetuses at risk of preterm birth. It was adopted worldwide to prevent neonatal death and neonatal complications following preterm birth, including respiratory distress syndrome, necrotizing enterocolitis and severe intraventricular hemorrhage. While short-term benefits of ACS were extensively investigated, long-term neurological outcomes in infants exposed antenatally to betamethasone have been assessed in few cohorts only. A recent report from the Cochrane collaborative network suggest that ACS is able to prevent some neurodevelopmental impairments associated with preterm delivery and related to postnatal adverse events . As of today, in Europe and France, more than 85% of neonates born very preterm have been exposed to antenatal corticosteroids, mostly betamethasone for a total dose of 24 mg. Cochrane collaborative networks stated that trials of dosages comparing different regimens of commonly used corticosteroids are most urgently needed. Because a half dosage was associated with maximal benefits on lung function in ewes, a randomized controlled trial (BETADOSE, NCT02897076) is currently conducted to demonstrate that a 50% reduced betamethasone dose regimen is not inferior to a full dose regimen to prevent respiratory distress syndrome in neonates. Whatever the results of this ongoing clinical trial, follow-up of infants born from enrolled women is mandatory both to confirm the non-inferiority of the dose reduction on neurocognition and to assess the long-term effect of dose reduction on survival, on complex aspects of cognition, on behavioral aspects and on others neurodevelopmental impairments. Indeed, changes in clinical practices following BETADOSE trials will be depending on both short- and long-term outcomes. If non inferiority is demonstrated, dramatic changes will occur in the clinical use of antenatal betamethasone in women at risk of preterm birth in France and worldwide. If non inferiority is rejected, the neurocognitive follow-up of enrolled patients will be also of interest to (i) assess the long-term impact of the early consequences associated with betamethasone dose reduction and (ii) to find out domains of neurocognitive development sensitive to ACS exposure. BETANINO study aims at assessing the impact of a 50% dose reduction on neurocognition at 5 years of age in infants born from mothers enrolled in the BETADOSE trial before 32 weeks of gestation, children that are at highest risk of neurocognitive impairments during childhood. The main hypothesis of this cohort study following a randomized clinical trial is that half dose betamethasone (12 mg) is not inferior to full dose betamethasone (24 mg) to prevent neurodevelopmental impairment in children born very preterm.