Table 2.
Postnatal growth and neurodevelopmental outcomes
| Cohort 1 (n = 56) | Cohort 2 (n = 56) | Mean difference (C2−C1) | 95% CI | |
|---|---|---|---|---|
| Growth velocity from birth through week 5 [g/kg/day; mean (SD)] | ||||
| Total cohort | 9.4 (3.0) | 11.3 (2.9) | 1.8 | 0.7 to 3.0 |
| Girls | 10.0 (2.7) | 10.7 (2.9) | 0.7 | −0.8 to 2.2 |
| Boys | 8.8 (3.4) | 11.8 (2.9) | 3.1 | 1.3 to 4.8 |
| Head circumference [standard deviation score; mean (SD)] | ||||
| Week 1 | −1.0 (1.1) | −1.6 (1.0) | −0.5 | −1.0 to −0.1 |
| Month 6 | −0.1 (1.3) | 0.05 (0.9) | 0.2 | −0.3 to 0.6 |
| Month 6–week 1* | 1.1 (0.7) | 1.7 (0.8) | 0.6 | 0.2 to 0.9 |
| Anthropometry at CA of 24 months [standard deviation score; mean (SD)] | ||||
| Head circumference | −0.2 (1.2) | −0.2 (1.0) | 0.0 | −0.4 to 0.4 |
| Weight | −0.7 (1.0) | −0.6 (0.9) | 0.1 | −0.8 to 0.4 |
| Length | −0.5 (1.0) | −0.4 (0.9) | 0.2 | −0.8 to 0.6 |
| BSID‐II [continuous scores; mean (SD)] | ||||
| MDI total cohort | 98 (13) | 99 (14) | 1.1 | −4.4 to 6.6 |
| Girls | 103 (10) | 103 (12) | −0.4 | −6.4 to 5.5 |
| Boys | 90 (14) | 96 (16) | 6.0 | −3.5 to 15.4 |
| PDI total cohort | 84 (16) | 87 (17) | 3.1 | −3.4 to 9.5 |
| Girls | 88 (16) | 90 (17) | 1.7 | −7.2 to 10.6 |
| Boys | 79 (16) | 84 (17) | 5.7 | −3.6 to 15.0 |
| OR (C 1 versus C 2) | 95% CI | |||
| BSID‐II [dichotomous; number (%)] | ||||
| MDI < 85 (n) | 16 (29) | 9 (16) | 2.1 | 0.9 to 5.4 |
| MDI ≥ 85 (n) | 39 (71) | 47 (84) | ||
| PDI < 85 (n) | 33 (59) | 30 (54) | 1.2 | 0.6 to 2.6 |
| PDI ≥ 85 (n) | 23 (41) | 26 (46) | ||
C1 = Cohort 1; C2 = Cohort 2; OR = Odds ratio; 95% CI = 95% Confidence interval; Month 6–week 1* = Change in SDS from birth until six months of corrected age (CA); BSID‐II = Bayley Scores of Infant Development – Second Edition at 24 months CA 14; MDI = Mental Developmental Index (n = 45/56); PDI = Psychomotor Developmental Index (n = 54/54); MDI and PDI < 85 = Moderately to severely impaired mental or psychomotor development, including not being able to perform the BSID‐II.
Growth velocity (n = 54/54) calculated using the exponential formula described by Patel et al. 11. Head circumference standard deviation score (HC SDS) calculated using the Swedish growth reference for preterm infants and the Dutch reference of the nationwide growth study at six months CA (week 1 n = 45/42; month 6 = 52/51; month 6–week 1 n = 46/40) 12, 13. Weight and length SDSs were calculated using the Dutch reference 12.