Single Dose of Antenatal Corticosteroids for Pregnancies at Risk of Preterm Delivery (SNACS)

Preterm infants are at risk of mortality and morbidity. Antenatal corticosteroids (ACS) reduce the risks of neonatal death and morbidities, such as respiratory distress syndrome. The standard of care for pregnant people at risk of preterm birth includes 2 doses of Celestone to accelerate fetal lung maturity (total 24 mg in Canada, 22.8 mg in Australia). There are no published clinical trial data on the benefits or risks of a single dose of antenatal corticosteroid vs. standard double doses (Ninan et al JOGC 2020). Pregnant people at 22 weeks and 0 days to \< 34 weeks and 6 days' gestation at risk of preterm birth with a singleton or twin gestation who have received the first dose of Celestone and consented to the trial will be randomized to receive approximately 24 hours later either an experimental placebo injection (of normal saline) or the standard double dose of Celestone to determine whether the intervention is non-inferior for the primary outcome of a composite of perinatal mortality or substantial morbidity. Please note: Based on Health Canada's' guidance the study phase is 'Other: Off-Label use'. However, on the clincaltrial.gov record, 'Phase 4' is selected as this is the most relevant phase and there is no option to select 'Other'. Please note: McMaster University, Canada is the Canadian Regulatory Sponsor and Overall Sponsor, and the University of Adelaide Australia is the Australian Sponsor.