Comparison 1. Oropharyngeal colostrum (OPC) versus control (water, saline, or no intervention).

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Incidence of necrotising enterocolitis (NEC)	6	335	Risk Ratio (M‐H, Fixed, 95% CI)	1.42 [0.50, 4.02]
2 Incidence of late‐onset infection	6	335	Risk Ratio (M‐H, Fixed, 95% CI)	0.86 [0.56, 1.33]
3 Death before discharge to home	6	335	Risk Ratio (M‐H, Fixed, 95% CI)	0.76 [0.34, 1.71]
4 Days to full enteral feed	6	335	Mean Difference (IV, Fixed, 95% CI)	‐2.58 [‐4.01, ‐1.14]
5 Length of hospital stay	4	293	Mean Difference (IV, Fixed, 95% CI)	0.81 [‐5.87, 7.50]
6 Pneumonia	3	57	Risk Ratio (M‐H, Fixed, 95% CI)	2.08 [0.54, 8.06]
7 Reported adverse effects			Other data	No numeric data
8 Chronic lung disease (CLD)	4	206	Risk Ratio (M‐H, Fixed, 95% CI)	0.85 [0.60, 1.20]
8.1 CLD	3	57	Risk Ratio (M‐H, Fixed, 95% CI)	1.11 [0.40, 3.08]
8.2 CLD and BPD	1	149	Risk Ratio (M‐H, Fixed, 95% CI)	0.81 [0.57, 1.17]
9 Days of antibiotic therapy	3	140	Mean Difference (IV, Random, 95% CI)	1.69 [‐2.00, 7.39]
10 Receiving any breast milk at discharge to home.	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
10.1 Fortified breast milk	1	99	Risk Ratio (M‐H, Fixed, 95% CI)	0.67 [0.44, 1.02]
10.2 Unfortified breast milk	1	99	Risk Ratio (M‐H, Fixed, 95% CI)	0.98 [0.89, 1.07]
10.3 Any breast milk (fortified or unfortified)	1	99	Risk Ratio (M‐H, Fixed, 95% CI)	0.61 [0.38, 0.97]
11 Days of parenteral nutrition	2	179	Mean Difference (IV, Fixed, 95% CI)	0.37 [‐1.78, 2.52]
12 Weight at discharge to home	1	149	Mean Difference (IV, Fixed, 95% CI)	24.5 [‐69.66, 118.66]
13 Retinopathy of prematurity (ROP)	2	165	Risk Ratio (M‐H, Fixed, 95% CI)	0.98 [0.33, 2.94]