1. Participant characteristics of individual trials.

	Allocation arm	Participants (N)	Birthweight (grams)	Gestational age (weeks)	Antenatal steroids(%)	Surfactant(%)	Starting dose (mg/kg/d)	Cumulative dose (mg/kg)‍‍	Mean age initiation	Total duration(days)	Late rescue corticosteroids (%)	Entry FiO₂ (%)	Entry MAP (cmH₂0)
Lower cumulative dosage (experimental arm) versus higher cumulative dosage (control arm)
Cummings 1989	High	13	818 ± 145	26 ± 2	38	0	0.5	7.9	14	42	0	0.60 ± 0.27	10.4 ± 6.0
	Moderate	12	810 ± 208	26 ± 2	25	0	0.5	3.0		18	0	0.51 ± 0.23	8.8 ± 2.7
DeMartini 1999	High	16	741 ± 142	25.5 ± 1.7	62	100	0.5	4.1	?	21	0	0.61 ± 26.9	?
	Moderate	14	848 ± 224	26.4 ± 1.6	64	100	0.5	2.7		7	0	0.60 ± 25.2
Marr 2019a	High	30	769 ± 149	25.2 ± 1.2	63	97	0.5	7.96	14 ± 4	42	20	0.72 ± 0.13	10.3 ± 2.0
	Moderate	29	785 ± 167	25.2 ± 1.1	62	86	0.5	4.04	13 ± 3	9b	37	0.77 ± 0.16	10.4 ± 1.7
Malloy 2005	Moderate	9c	767 ± 149	25.8 ± 0.9	75	100	0.5	2.7	14.8 ± 6.5	7	88	0.57 ± 0.08	?
	Low	8	773 ± 182	26.1 ± 1.8	63	100	0.08	0.6	16.8 ± 5.7	7	50	0.52 ± 0.16
Durand 2002	Moderate	23	932 ± 182	27.1 ± 1.8	52	87	0.5	2.4	11.5 ± 2.2	7	22	0.43 ± 0.11	7.8 ± 2.2
	Low	24	858 ± 186	26.9 ± 1.6	50	88	0.2	1.0	11.3 ± 2.7	7	29	0.41 ± 0.10	7.0 ± 1.2
McEvoy 2004	Moderate	29	839 ± 229	26.1 ± 2.0	34	97	0.5	2.4	10.7 ± 3.7	7	55	0.44 ± 0.13	6.8 ± 1.8
	Low	33	830 ± 248	26.3 ± 1.8	48	82	0.2	1.0	11.6 ± 4.3	7	39	0.42 ± 0.13	7.4 ± 2.2
Ramanathan 1994	Moderate	15	850 ± 290	27 ± 2	?	67	0.4	1.9d	10 to 14	7	67	?	?
	Low	13	817 ± 186	27 ± 2		62	0.2	1.0d		7	54
Da Silva 2002	Moderate	17	821 ± 160	25.4 ± 0.9	?	?	0.5	?	?	7	?	?	?
	Low	21	851 ± 465	25.7 ± 1.8			0.1	0.7		7
Later initiation (experimental arm) versus earlier (control arm)
Papile 1998	ME	182	808 ± 187	25.7 ± 1.9	29	91	0.5	3.7	14	14	12	0.54 ± 0.18	8 ± 2
	L	189	801 ± 182	25.6 ± 1.6	27	89			28		16	0.54 ± 0.19	8 ± 2
Merz 1999	E	15	980 (710 to 1250)	27 (25 to 29)	87	87	0.5	3.1	7	16	0	0.3 (0.25 to 0.5)	?
	ME	15	938 (680 to 1250)	27.5 (24 to 29)	73	73			14		0	0.3 (0.25 to 0.55)
Halliday 2001a	E	135	1017 ± 290	27.4 ± 1.9	61	95	0.5	2.7	3	12	?	?	?
	ME	150	1007 ± 283	27.1 ± 1.9	55	92			16
Hingre 1992	E	14	744 ± 144	26 ± 2	?	?	0.5	7.96	5	42	?	?	?
	ME	21	730 ± 135e	25 ± 2					14
Pulse dosage regimen (experimental arm) versus continuous dosage regimen (control arm)
Bloomfield 1998	Pulse/Ef	39	776 ± 25	25.8 ± 0.3	95	?	0.5	5.3 (1.5 to 11.8)	7	34 (11 to 73)	?	0.30 ± 0.02	8.0 ± 0.3
	Cont/ME	37	793 ± 28	25.8 ± 0.3	73		0.5	7.1 (4.5 to 7.6)	14	42 (42 to 51)		0.30 ± 0.01	7.8 ± 0.3
Barkemeyer 2001	Pulse	58	816	26.1	84	92	0.5	4.5	7 to 21	23	41	?	?
	Cont	63	842	26.2	78	88					36
Individualized tailored (experimental arm) versus standard dosage regimen (control arm)
Odd 2004	Indiv	17	669 ± 113	24 (23 to 27)	?	?	0.5	3.8 (2.0 to 5.7)	12 (7 to 16)	42 (5 to 73)	?	0.40 (0.25 to 1.0)	9 (7 to 14)
	Cont	16	720 ± 130	24 (23 to 26)			0.5	7.9	10 (7 to 23)	42		0.40 (0.21 to 1.0)	9 (7 to 13)

^a Marr not only in higher versus lower comparison, but also in individual tailored versus standard dosage regimen
^b 19 of the 29 infants (66%) received one course, 5 infants (17%) 2 courses, and 5 infants (17%) 3 courses of dexamethasone
^c Including one patient in high dose group who died on the second day of treatment
^d Estimated cumulative dose based on abstract data
^e participant characteristics calculated on 16 participants in the moderately early group
^f Bloomfield not only pulse versus continuous comparison, but also in early versus later initiation and in individualized tailored versus standard dosage regimens comparison

Mean ± standard deviation or median (interquartile range)

Abbreviations: FiO₂: fractional inspired oxygen; MAP: mean airway pressure; E: Early initiation (≤ 7 days' PNA); ME: Moderately early initiation (7 to 14 days' PNA); L: Late initiation (> 14 days' PNA); Pulse: Pulse dosage regimen; Cont: Continuous tapered dosage regimen; Indiv: Individual tailored regimen.