Table 1.
Descriptive characteristics of the study sample (N = 131).
| Median [range] or n (%) | |
|---|---|
| Clinical characteristics | |
| Child sex, male | 67 (51.1) |
| PMA at birth (weeks) | 29 + 5 [23 + 3; 31 + 6] |
| Birth weight (g) | 1140 [410; 2120] |
| Height at birth (cm) | 38 [25; 47] |
| APGAR | |
| 5 min after birth | 8 [2; 10] |
| 10 min after birth | 9 [3; 10] |
| Multiple births | 36 (27.5) |
| Umbilical cord pH at birtha | 7.3 [6.9; 7.5] |
| Sepsisb | 41 (31.5) |
| PDAc | 64 (49.6) |
| IVH ≥ grade 2 | 10 (7.6) |
| PVL | 2 (1.5) |
| ROP ≥ grade 2d | 18 (20.6) |
| BPD, moderate and severee | 8 (6.4) |
| NECb | 2 (1.5) |
| FIPc | 5 (3.9) |
| Follow-up characteristics | |
| T1, gestational age (weeks) | 35 [33; 37] |
| T2, corrected age (weeks) | 13 [11; 15] |
| T3, corrected age (months)f,h | 12 [11; 15] |
| Parental educationg,i | |
| High | 40 (33.1) |
| Middle | 72 (59.5) |
| Low | 9 (7.4) |
Data are presented as median [range] for continuous variables and numbers (percentage) for categorical variables.
PMA postmenstrual age; APGAR score based on appearance, pulse, grimace, activity, and respiration; PDA persistent ductus arteriosus; IVH intraventricular hemorrhage; PVL periventricular leukomalacia; ROP retinopathy of prematurity; BPD bronchopulmonary dysplasia; NEC necrotizing enterocolitis; FIP focal intestinal perforation.
Descriptive statistics are based on an = 122, bn = 130, cn = 129, dn = 87, en = 126, fn = 95 and gn = 121 and infants, otherwise n = 131.
hThe age at T3 is the same regardless of the composition of the reduced sample for the individual BSID-III scale (cognition, fine and gross motor).
iParental education is defined as the highest educational qualification held by either parent and was coded according to the International Standard Classification of Education (ISCED) into low (level 0–2), middle (level 3–4), and high (level 5–8)34.