A systematic review and meta-analysis of the nutrient content of preterm and term breast milk

BMC Pediatrics

Table 4 Meta-analysis results of preterm and term breast milk protein content over time

Comparison: True protein comparisons: Preterm vs. term (g/dL)♦
	Preterm			Term		Preterm & term compared
Time frame:	mean	SD	n	mean	SD	n	% difference	p-values
d 1-3	2.7	1.5	141	2.0	0.9	108	35	< 0.00001*
d 4-7	1.7	0.5	165	1.6	0.3	185	7	0.005
week 2	1.5	0.4	191	1.3	0.2	256	16	< 0.00001*
week 3-4	1.4	0.4	92	1.1	0.2	194	27	< 0.00001*
week 5-6	1.1	0.2	38	1.0	0.1	85	7	0.0003
week 7-9	1.1	0.2	30	0.9	0.1	113	20	< 0.00001*
week 10-12	1.0	0.2	25	1.0	0.1	221	2	0.37
♦ References: [11–14, 18, 19, 121–123, 127–129, 136–139]
Comparison: Total protein comparisons: Preterm vs. term (g/dL)♦♦
	Preterm			Term		Preterm & term compared
Time frame:	mean	SD	n	mean	SD	n	% difference	p-values
d 1-3	2.8	1.1	94	2.0	0.6	168	37	< 0.00001*
d 4-7	2.1	0.5	244	2.0	0.5	229	4	0.04
week 2	1.9	0.4	253	1.8	0.4	192	8	< 0.00001*
week 3-4	1.6	0.4	439	1.5	0.3	210	9	0.01
week 5-6	1.4	0.3	268	1.1	0.2	357	18	< 0.00001*
week 7-9	1.1	0.2	183	1.3	0.2	453	−10	< 0.00001*
week 10-12	1.3	0.3	18	1.2	0.2	109	12	0.07
♦♦ References: [6, 11–14, 18–23, 120, 122, 123, 125, 128–135]
Comparisons: True vs. Total protein ♦♦♦
	Difference	% difference	p-value	Difference	% difference	p-value
d 1-3	0.1	4%	0.60	0	1%	0.91
d 4-7	0.3	20%	< 0.00001*	0.4	24%	< 0.00001*
week 2	0.4	26%	< 0.00001*	0.5	36%	< 0.00001*
week 3-4	0.2	12%	< 0.00001*	0.4	31%	< 0.00001*
week 5-6	0.3	27%	< 0.00001*	0.1	11%	< 0.00001*
week 7-9	0	3%	0.35	0.3	37%	< 0.00001*
week 10-12	0.3	32%	0.0002	0.2	20%	< 0.00001*

♦♦♦Estimates based on true protein content versus the assumption that all nitrogen is protein.
*Statistically significant difference. In compensation for multiple comparisons, an approximate Bonferroni adjustment was made and the p-value for statistical significance was < 0.001.

ISSN: 1471-2431