TABLE 5.
Characteristics of the 4 Clusters for Longitudinal Changes in WISC-III Block-Design Raw Scores
| Cluster A* | Cluster B* | Cluster C* | Cluster D* | |
|---|---|---|---|---|
| N | 145 | 67 | 41 | 62 |
| Proportion of total preterm cohort (N = 315), % | 46 | 21 | 13 | 20 |
| Child characteristics | ||||
| Gestational age, mean (SD), wk | 28.1 (1.9) | 27.8 (1.8) | 28.5 (2.0) | 27.3 (2.0) |
| Birth weight, mean (SD), g | 976 (168) | 953 (167) | 987 (180) | 913 (173) |
| Male gender, n (%) | 75 (52) | 33 (49) | 24 (58) | 37 (60) |
| Multiple, n (%) | 37 (26) | 10 (15) | 10 (24) | 11 (18) |
| Small for gestational age, n (%) | 41 (28) | 13 (19) | 11 (27) | 10 (16) |
| Maternal steroids, n (%) | 61 (42) | 24 (36) | 13 (32) | 12 (19) |
| Indomethacin, n (%) | 64 (45) | 39 (60) | 23 (56) | 31 (52) |
| Bronchopulmonary dysplasia, n (%) | 56 (39) | 33 (49) | 20 (49) | 32 (52) |
| Neonatal brain injury, n (%) | ||||
| None | 112 (77) | 53 (79) | 32 (78) | 39 (63) |
| Severe brain injurya | 6 (4) | 4 (6) | 3 (7) | 14 (23) |
| NSI, n (%) | 6 (4) | 8 (12) | 1 (2) | 28 (45) |
| Family factors | ||||
| Maternal age at birth, mean (SD), y | 28.1 (6.2) | 27.6 (5.8) | 27.1 (6.1) | 27.3 (5.9) |
| Maternal education, n (%) | ||||
| High school or less | 44 (30) | 30 (45) | 18 (44) | 34 (56) |
| ≥1 year of college | 101 (70) | 37 (55) | 23 (56) | 27 (44) |
| Race and ethnicity, n (%) | ||||
| Non-Hispanic white | 114 (79) | 45 (67) | 21 (52) | 33 (53) |
| Other | 31 (21) | 22 (33) | 19 (48) | 29 (47) |
| Single-parent household at the age of 16 y, n (%) | 12 (24) | 22 (34) | 32 (28) | 35 (45) |
a
Severe brain injury includes grades 3 to 4 intraventricular hemorrhage, periventricular leukomalacia, and grade 2 and above ventriculomegaly.