Table 5.

Rate of catch-up growth in the different BW groups (%, n/N)

	VLBW	LBW	NBW
Weight
0–6 Mon	29(29/100)	26.5(117/441)	24.7(41/166)
0–12 Mon	35.1(33/94) ab	22.2(100/451) a	16.9(29/172) b
Length
0–6 Mon	50(50/100) ab	28(123/441) ac	16.9(28/166) b
0–12 Mon ac	48.9(46/94) ab	30.1(136/451)	15.7(27/172) bc
HC
0–6 Mon	19(19/100) b	13.4(59/441) c	6(10/166) bc
0–12 Mon	29.8(28/94) ab	14.1(64/451) ac	7.5(13/172) bc

A: significant difference between the VLBW and LBW groups, p < 0.01

B: significant difference between the VLBW and NBW groups, p < 0.01

C: significant difference between the LBW and NBW groups, p < 0.01

Mon: months; HC: head circumference; VLBW:very low birth weight, birth weight < 1500 g; LBW: low birth weight, 1500 g ≤ birth weight < 2500 g; NBW:normal birth weight,2500 ≤ birth weight<4000 g. Catch-up growth: a change in the Z-score > 0.67 between two time points. Chi-square test or Fisher’s exact test was used to analyze