TABLE 2.
Growth and body composition parameters from birth to 6 months
| Birth | Weight nadir | Transfer NICU to level‐II hospital | Discharge home | 2 M‐visit | 6 M‐visit | ||
|---|---|---|---|---|---|---|---|
| Growth 1 | n | 120 | 120 | 120 | 119 | 119 | 113 |
| Gestational/corrected age2 | weeks +days | 27+5 (26+1;28+5) | 28+2 (26+5;29+1) | 32+0 (30+3;36+1) | 39+5 (38+0;41+5) a | 7+4 (6+4;9+6) | 26+3 (25+2;27+5) |
| Postnatal age | days | 1 | 5 (3;6) | 29 (17;67) | 84 (68;104) a | 138 (128;163) | 273 (261;286) |
| Weight | kg | 1.02 (0.80;1.25) | 0.89 (0.73;1.10) | 1.45 (1.25;2.04) | 3.11 (2.71;3.59) a | 4.73 (4.15;5.30) | 7.19 (6.42;7.73) |
| Z‐score | 0.1 (−0.4;0.7) | −0.7 (−1.2;‐0.3) | −0.9 (−1.5;‐0.4) | −0.7 (−1.7;0.1) a | −0.8 (−1.6;‐0.1) | −0.7 (−1.5;0.1) | |
| Head circumference | cm | 24.8 (23.7;26.6) b | NA | 28.0 (26.9;31.4) c | 34.5 (33.2;36.3) d | 38.7 (37.5;40.0) b | 43.4 (42.0;44.2) b |
| Z‐score | 0.1 (−0.5;0.6) b | NA | −0.8 (−1.4;‐0.3) c | −0.1 (−1.1;0.6) d | 0.2 (−0.7;1.0) b | 0.3 (−0.5;1.0) b | |
| Length | cm | NA | NA | 38.0 (36.6;42.4) e | 48.0 (46.0;50.3) f | 55.2 (53.6;57.2) a | 66.4 (64.0;68.5) g |
| Z‐score | NA | NA | −1.6 (−2.6;−1.0) e | ‐1.0 (−2.1;‐0.6) f | −1.1 (−1.9;‐0.3) a | −0.2 (−1.2;0.5) g | |
| Body composition | n | 103 | 92 | ||||
| Relative fat mass | % | NA | NA | NA | NA | 21.9 (17.8;23.9) | 20.4 (18.0;23.3) |
| Z‐score | NA | NA | NA | NA | 0.5 (−0.4;1.1) | −0.6 (−1.3;‐0.1) | |
| Absolute fat mass | kg | NA | NA | NA | NA | 0.98 (0.78;1.30) | 1.44 (1.12;1.70) |
| Z‐score | NA | NA | NA | NA | 0.0 (−0.8; 0.8) | −0.8 (−1.5;‐0.2) | |
| Fat mass index | kg/m 2 | NA | NA | NA | NA | 3.42 (2.66;3.95) | 3.25 (2.76;3.87) |
| Z‐score | NA | NA | NA | NA | 0.3 (−0.4;1.1) | −0.6 (−1.2;‐0.1) | |
| Absolute lean mass | kg | NA | NA | NA | NA | 3.70 (3.33;4.04) | 5.65 (5.08;6.08) |
| Z‐score | NA | NA | NA | NA | −0.9 (−1.6;‐0.3) | −0.4 (−1.2;0.3) | |
| Lean mass index | kg/m 2 | NA | NA | NA | NA | 12.04 (11.32;12.82) | 12.67 (12.0;13.4) |
| Z‐score | NA | NA | NA | NA | −0.1 (−0.8;0.8) | 0.1 (−0.6;0.6) |
Note: All data are expressed in median (interquartile range) or number (percentages). Length measurement was not routinely collected during NICU and level‐II hospital stay, leading to many missing values. Z‐scores for body composition parameters were calculated based on average values from a large group of term born infants assessed at our research center within the same time period. 1 Missing growth data of one infant at discharge home, one infant at 2 M‐visit (no appointment at outpatient clinic) and seven infants at 6 M‐visit (4 no appointment at outpatient clinic, 3 no show for appointment). 2 Gestational age for birth until discharge home, corrected age for 2 M‐ and 6 M‐visits.
Abbreviations: cm, centimeter; m, meter; M, month; NICU, neonatal intensive care unit; n, number; kg, kilograms.
Number of infants with missing data:
2 Infants,
3 Infants,
14 Infants,
44 infants,
64 infants,
71 infants,
1 infant.