Comparison 2. Correction for cluster effect.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
2.1 Change in weight in the first 2 years of life	4	795	Mean Difference (IV, Fixed, 95% CI)	‐0.01 [‐0.09, 0.07]
2.2 Change in height in the first 2 years of life	4	795	Mean Difference (IV, Fixed, 95% CI)	‐0.02 [‐0.20, 0.17]
2.3 Weight‐for‐age z score at 12 months of age	6	1330	Mean Difference (IV, Fixed, 95% CI)	0.19 [0.10, 0.28]
2.4 Weight‐for‐age z score at 18 months of age	4		Mean Difference (IV, Random, 95% CI)	Subtotals only
2.5 Height‐for‐age z score at 12 months of age	7	1433	Mean Difference (IV, Fixed, 95% CI)	0.18 [0.08, 0.28]
2.6 Height‐for‐age z score at 18 months of age	5	2012	Mean Difference (IV, Fixed, 95% CI)	0.17 [0.08, 0.26]
2.7 Weight‐for‐height z score at 12 months of age	5	966	Mean Difference (IV, Fixed, 95% CI)	0.11 [‐0.02, 0.23]
2.8 Weight‐for‐height z score at 18 months of age	5	1989	Mean Difference (IV, Random, 95% CI)	0.21 [‐0.04, 0.47]
2.9 Death before 1 year of age	4	2400	Risk Ratio (M‐H, Fixed, 95% CI)	0.70 [0.37, 1.29]
2.10 Exclusive breastfeeding at 6 months of age	3	1859	Risk Ratio (M‐H, Random, 95% CI)	1.36 [0.73, 2.56]