Table 1.

Characteristics of included studies

Author (year)	Participants	Study design	Timing of hydrocortisone: Early (≤7 days) or late (≥8 days)	Dates	Intervention participants	Control participants	Primary outcome
Baden (1972) [18]	Preterm infants	Randomised controlled trial	Early	Aug 1971–Apr 1972	N = 22	N = 22	Respiratory distress syndrome course and survival
Batton (2012) [19]	Preterm infants 23 + 0–26 + 6 weeks gestation	Randomised controlled trial	Early	Dec 2009–Dec 2010	N = 4	N = 6	Feasibility study (enrolment)
Baud (2016) [20]	Preterm infants 24 + 0–27 + 6 weeks gestation	Randomised controlled trial	Early	May 2008–Jan 2014	N = 255	N = 266	Survival without BPD at 36 weeks postmenstrual age
Baud (2017) [31]	2-year follow-up of Baud (2016)	Randomised controlled trial	Early	May 2008–Jan 2014	N = 255	N = 266	2-year neurodevelopmental outcome (secondary outcome)
Biswas (2003) [21]	Preterm infants < 30 weeks gestation	Randomised controlled trial	Early	Jan 1996–Apr 1998	N = 125	N = 128	Death or ventilator dependence at 1 week
Bonsante (2007) [22]	Preterm infants 24–30 weeks gestation	Randomised controlled trial	Early	Apr 2003–Sep 2005	N = 25	N = 25	Survival without oxygen at 36 weeks postmenstrual age
Bourchier (1997) [23]	Preterm infants < 1500 g birth weight	Randomised controlled trial	Early	Jul 1993–Jun 1995	N = 21	N = 25	Persistent hypotension despite treatment
Efird (2005) [24]	Preterm infants 23 + 0–28 + 6 weeks gestation	Randomised controlled trial	Early	May 2000–May 2002	N = 16	N = 18	Need for treatment for hypotension with vasopressin
Fitzhardinge (1974) [32]	1-year follow-up of Baden (1972) [18]	Randomised controlled trial	Early	1971–exact dates not specified	N = 13	N = 13	Respiratory distress syndrome course and survival
Hochwald (2014) [25]	Preterm infants ≤ 30 weeks gestation	Randomised controlled trial	Early	Jan 2007–Dec 2009	N = 11	N = 11	Vasopressor dose in hypotension
Ng (2006) [26]	Preterm infants < 32 weeks gestation	Randomised controlled trial	Early	Jun 2001–Nov 2004	N = 24	N = 24	Treatment of refractory hypotension
Onland 2019 [38]	Preterm infants < 30 weeks gestation and/or < 1250 g birth weight	Randomised controlled trial	Late	Nov 2011–Dec 2016	N = 181	N = 190	Death or BPD at 36 weeks postmenstrual age
Parikh (2013) [37]	Preterm infants ≤ 1000 g birth weight	Randomised controlled trial	Late	Oct 2005–Sep 2008	N = 31	N = 33	Total brain tissue volume as per MRI at 38 weeks postmenstrual age
Parikh (2015) [39]	18–22-month follow-up of Parikh (2013) [37]	Randomised controlled trial	Late	Oct 2005–Sep 2008	N = 31	N = 33	Neurodevelopmental outcomes and mortality at 18–22 months (secondary outcome)
Peltoniemi (2005) [27]	Preterm infants 23 + 0–30 + 0 weeks gestation	Randomised controlled trial	Early	Aug 2002–Mar 2004	N = 25	N = 26	Survival without oxygen at 36 weeks postmenstrual age
Peltoniemi (2009) [33]	2-year follow-up of Peltoniemi (2005) [27].	Randomised controlled trial,	Early	Aug 2002–Mar 2004	N = 25	N = 26	Growth and development at 2 years (secondary outcome)
Peltoniemi (2016) [34]	5–7-year follow-up of Peltoniemi (2005) [27].	Randomised controlled trial	Early	Aug 2002–Mar 2004	N = 25	N = 26	Growth and development at 5–7 years of age (secondary outcome)
Watterberg (1999) [28]	Preterm infants 500-999 g birth weight	Randomised controlled trial	Early	Jun 1996–May 1998	N = 20	N = 20	Survival without oxygen at 36 weeks postmenstrual age
Watterberg (2004) [29]	Preterm infants 500-999 g birth weight	Randomised controlled trial	Early	Nov 2001–Apr 2003	N = 180	N = 180	Survival without oxygen at 36 weeks postmenstrual age
Watterberg (2007) [35]	18–22-month follow-up of Watterberg (2004) [29]	Randomised controlled trial	Early	Nov 2001–Apr 2003	N = 180	N = 180	Growth and neurodevelopmental outcome at 18–22 months corrected age (secondary outcome)