Number (%) and risk ratios for achieving ‘considerably above expected’ level in Key Stage 1 according to gestational age in the Millennium Cohort Study
| Outcome | Total n=6031 (%) | Very PT (<32 w) n=69 (%) | Moderately PT (32–33 weeks) n=67 (%) | Late PT (34–36 weeks) n=360 (%) | ET (37–38 weeks) n=1258 (%) | Full-term (39–41 weeks) n=4277 (%) |
|---|---|---|---|---|---|---|
| Achieving level 3 (‘considerably above expected’) in reading, writing and mathematics | ||||||
| Achieved | 636 (10) | * | * | 33 (8) | 143 (11) | 450 (10) |
| RR (95% CI) achieved† | 0.92 (0.88 to 0.96) | 1.02 (0.90 to 1.15) | 0.97 (0.94 to 1.01) | 1.01 (0.98 to 1.02) | 1 | |
| aRR (95% CI) achieved‡ | 0.94 (0.89 to 1.0) | 1.01 (0.92 to 1.12) | 0.97 (0.94 to 1.00) | 1.01 (0.96 to 1.04) | 1 | |
| Reading: level 3 | ||||||
| Achieved | 1701 (27) | 11 (20) | 11 (15) | 95 (26) | 343 (26) | 1241 (28) |
| RR (95%CI) achieved† | 0.89 (0.78 to 1.03) | 0.84 (0.74 to 0.96) | 0.96 (0.89 to 1.03) | 0.96 (0.92 to 1.0) | 1 | |
| aRR (95% CI) achieved‡ | 0.97 (0.83 to 1.14) | 0.89 (0.74 to 0.93) | 0.97 (0.92 to 1.04) | 0.98 (0.94 to 1.02) | 1 | |
| Writing: level 3 | ||||||
| Achieved | 808 (13) | * | * | 45 (19) | 181 (13) | 571 (13) |
| RR (95% CI) achieved† | 0.90 (0.85 to 0.95) | 0.99 (0.88 to 1.12) | 0.97 (0.93 to 1.01) | 1.01 (0.98 to 1.03) | 1 | |
| aRR (95% CI) achieved‡ | 0.93 (0.86 to 1.01) | 0.98 (0.89 to 1.09) | 0.97 (0.94 to 1.01) | 1.01 (0.98 to 1.04) | 1 | |
| Speaking and listening: level 3 | ||||||
| Achieved | 1423 (23) | 10 (16) | 14 (17) | 79 (21) | 306 (24) | 1014 (24) |
| RR (95% CI) achieved† | 0.92 (0.81 to 1.03) | 0.93 (0.80 to 1.06) | 0.97 (0.91 to 1.03) | 1.00 (0.97 to 1.03) | 1 | |
| aRR (95% CI) achieved‡ | 0.95 (0.84 to 1.09) | 0.91 (0.80 to 1.02) | 0.97 (0.92 to 1.03) | 1.02 (0.98 to 1.05) | 1 | |
| Mathematics: level 3 | ||||||
| Achieved | 1475 (24) | * | * | 82 (22) | 316 (24) | 1059 (24) |
| RR (95% CI) achieved† | 0.81 (0.75 to 0.89) | 0.92 (0.79 to 1.05) | 0.97 (0.91 to 1.04) | 1.00 (0.96 to 1.04) | 1 | |
| aRR (95% CI) achieved‡ | 0.86 (0.78 to 0.94) | 0.88 (0.79 to 0.99) | 0.97 (0.91 to 1.04) | 1.00 (0.96 to 1.04) | 1 | |
| Science: level 3 | ||||||
| Achieved | 1496 (24) | * | * | 85 (24) | 304 (23) | 1085 (25) |
| RR (95% CI) achieved† | 0.89 (0.78 to 1.03) | 0.89 (0.78 to 1.03) | 0.98 (0.92 to 1.05) | 0.98 (0.94 to 1.02) | 1 | |
| aRR (95% CI) achieved‡ | 0.96 (0.83 to 1.11) | 0.87 (0.78 to 0.98) | 1.00 (0.93 to 1.08) | 0.99 (0.95 to 1.02) | 1 | |
All percentages are weighted. *Due to statistical disclosure guidelines to ensure confidentiality, the raw data for mathematics performance in the very preterm and moderately preterm groups are not reported.
†RR adjusted for multiple birth.
‡aRR adjusted for child's sex, child's age in school year taking into account premature children who if born at full term would have been placed in the year below, multiple birth, firstborn status, mother's age, mother's education, mother's social class, marital status, smoking during pregnancy.