Number (%) and risk ratios for not achieving the expected level in Key Stage 1 according to gestational age in the Millennium Cohort Study
| Outcome | Total n=6031 (%) | Very preterm (<32 weeks) n=69 (%) | Moderately preterm (32–33 weeks) n=67 (%) | Late preterm (34–36 weeks) n=360 (%) | Early term (37–38 weeks) n=1258 (%) | Full-term (39–41 weeks) n=4277 (%) |
|---|---|---|---|---|---|---|
| Primary outcome: achieving level 2 (expected) or above in reading, writing and mathematics | ||||||
| Not achieved | 1113 (19) | 29 (43) | 18 (31) | 84 (25) | 237 (21) | 745 (18) |
| RR (95% CI) not achieved* | 2.41 (1.80 to 3.22) | 1.74 (1.06 to 2.85) | 1.41 (1.12 to 1.78) | 1.18 (1.01 to 1.36) | 1 | |
| aRR (95% CI) not achieved† | 1.78 (1.24 to 2.54) | 1.71 (1.15 to 2.54) | 1.36 (1.09 to 1.68) | 1.07 (0.94 to 1.23) | 1 | |
| Reading: level 2 (expected) or above | ||||||
| Not achieved | 767 (14) | 18 (30) | 13 (22) | 65 (19) | 181 (16) | 490 (12) |
| RR (95% CI) not achieved* | 2.49 (1.67 to 3.73) | 1.82 (1.03 to 3.20) | 1.61 (1.23 to 2.11) | 1.36 (1.14 to 1.62) | 1 | |
| aRR (95% CI) not achieved† | 1.84 (1.12 to 3.05) | 1.82 (1.12 to 2.98) | 1.55 (1.20 to 2.00) | 1.22 (1.04 to 1.44) | 1 | |
| Writing: level 2 (expected) or above | ||||||
| Not achieved | 987 (17) | 27 (40) | 16 (28) | 74 (22) | 205 (18) | 665 (16) |
| RR (95% CI) not achieved* | 2.54 (1.87 to 3.45) | 1.75 (1.07 to 2.85) | 1.41 (1.12 to 1.79) | 1.13 (0.96 to 1.35) | 1 | |
| aRR (95% CI) not achieved† | 1.82 (1.24 to 2.68) | 1.69 (1.14 to 2.50) | 1.35 (1.07 to 1.71) | 1.03 (0.88 to 1.21) | 1 | |
| Speaking and listening: level 2 (expected) or above | ||||||
| Not achieved | 623 (11) | 20 (29) | 11 (15) | 47 (12) | 150 (14) | 395 (9) |
| RR (95% CI) not achieved* | 3.13 (2.15 to 4.56) | 1.58 (0.81 to 3.08) | 1.33 (0.93 to 1.89) | 1.46 (1.19 to 1.79) | 1 | |
| aRR (95% CI) not achieved† | 2.48 (1.63 to 3.78) | 1.58 (0.79 to 3.17) | 1.36 (0.96 to 1.94) | 1.31 (1.08 to 1.60) | 1 | |
| Mathematics: level 2 (expected) or above | ||||||
| Not achieved | 490 (8) | ‡ | ‡ | 31 (8) | 124 (11) | 313 (7) |
| RR (95% CI) not achieved* | 2.65 (1.51 to 4.66) | 2.05 (0.94 to 4.43) | 1.07 (0.68 to 1.71) | 1.50 (1.20 to 1.8) | 1 | |
| aRR (95% CI) not achieved† | 1.89 (0.92 to 3.64) | 1.96 (0.97 to 3.99) | 1.03 (0.66 to 1.59) | 1.38 (1.11 to 1.72) | 1 | |
| Science: level 2 (expected) or above | ||||||
| Not achieved | 560 (10) | 17 (22) | 11 (19) | 42 (11) | 137 (12) | 353 (8) |
| RR (95% CI) not achieved* | 2.63 (1.66 to 4.17) | 2.21 (1.11 to 4.41) | 1.36 (0.95 to 1.95) | 1.42 (1.15 to 1.74) | 1 | |
| aRR (95% CI) not achieved† | 1.87 (0.93 to 3.74) | 2.25 (1.16 to 4.38) | 1.33 (0.91 to 1.94) | 1.28 (1.06 to 1.55) | 1 | |
All percentages are weighted. *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.
‡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.