Garite 1992.

Study characteristics
Methods	Type of study: RCT Method of treatment allocation: random‐number table generated randomisation sequence by pharmacy. The pharmacy provided consecutive sealed envelopes. Stratification: none stated Placebo: yes, normal saline Sample size calculation: no Intention‐to‐treat analyses: no Losses to follow‐up: yes, 5 (7%) women delivered elsewhere and were lost to follow‐up (4 in treatment arm and 1 in control arm)
Participants	Location: Long Beach Memorial Women's Hospital, California, USA Eligibility criteria: women likely to deliver between 24 hours and 7 days with spontaneous preterm labour or planned preterm delivery Gestational age range: 24‐27 + 6 weeks Exclusion criteria: PROM, clinical or laboratory evidence of infection, contraindication to or previously given corticosteroids, diabetes Total recruited: 76 women and 82 infants; 37 women and 40 infants in the treatment arm and 39 women and 42 infants in the control arm
Interventions	2 doses of 6 mg betamethasone acetate and 6 mg betamethasone phosphate IM 24 hours apart, repeated weekly if still < 28 weeks and thought likely to deliver within the next week Control group received 2 doses of placebo. Women undelivered after 28 weeks and 1 week post their last dose of study medication were allowed glucocorticoids at the discretion of their physicians.
Outcomes	Maternal outcomes (chorioamnionitis, endometritis), fetal/neonatal outcomes reported (fetal death, neonatal death, RDS, chronic lung disease, IVH, birthweight, Apgar < 7, need for mechanical ventilation/CPAP, duration of mechanical ventilation/CPAP, proven neonatal infection while in NICU)
Notes	It is not stated how many women received corticosteroids off protocol. Study dates: December 1984‐May 1990 Funding sources: quote: "supported by a grant from the Long Beach Memorial Foundation" Declarations of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random‐number table generated randomisation sequence by pharmacy
Allocation concealment (selection bias)	Unclear risk	The pharmacy provided consecutive sealed envelopes, not stated if envelopes were opaque
Blinding of participants and personnel (performance bias) All outcomes	Low risk	It is likely that participants were blinded as placebo was used. Blinding of study personnel was not described other than "double‐blind"
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Blinding of outcome assessors was not described.
Incomplete outcome data (attrition bias) All outcomes	Low risk	5 (7%) women delivered elsewhere and were lost to follow‐up (4 in treatment arm and 1 in control arm).
Selective reporting (reporting bias)	Low risk	Study protocol not available, but appears to report on all pre‐specified outcomes
Other bias	Low risk	Nothing to indicate any other source of bias