Table 1

Cognitive scores of children born EP compared with controls from geographically defined cohorts from different countries

Country (reference)Years of birthGA (weeks)Age assessed (years)IQ Mean (SD)Mean difference
(95% CI)
<−2 SD
EPControlEP (%)Control (%)
Australia7

1991–199223–278.794.9 (16.5) n=198104.7 (14.1) n=212−8.0 (−10.9 to −5.1)*14.32.7
199722–278.493.8 (14.7) n=133105.6 (12.4) n=170−10.5 (−13.8 to −7.1)*9.91.8
200522–277.794.7 (15.7) n=137107.2 (10.9) n=189−10.2 (−13.3 to −7.1)*13.60
UK and Ireland8 199522–256.3†82.1 (19.2) n=241105.7 (11.8) n=160−24.0 (−27 to −20)40.71.3
France9 199724–275†90.0 (18.7) n=223106.4 (17.8) n=320−16.4 (−17.9 to −14.8)17.93.4
Sweden10 2004–200722–266.6†83.4 (14.8) n=371100.3 (11.7) n=367−14.2 (−16.3 to −12.1)*32.12.2
  • *Adjusted for sociodemographic variables.

  • †Age not corrected for prematurity.

  • EP, extremely preterm; GA, gestational age.