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*
N145674162
Proportion of total preterm cohort (N = 315), %46211320
Child characteristics
    Gestational age, mean (SD), wk28.1 (1.9)27.8 (1.8)28.5 (2.0)27.3 (2.0)
    Birth weight, mean (SD), g976 (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 (%)
        None112 (77)53 (79)32 (78)39 (63)
        Severe brain injurya6 (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), y28.1 (6.2)27.6 (5.8)27.1 (6.1)27.3 (5.9)
    Maternal education, n (%)
        High school or less44 (30)30 (45)18 (44)34 (56)
        ≥1 year of college101 (70)37 (55)23 (56)27 (44)
    Race and ethnicity, n (%)
        Non-Hispanic white114 (79)45 (67)21 (52)33 (53)
        Other31 (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.