Figure 1.

Association between gestational age at birth and school attainment at Key Stage 1 and Key Stage 2. Figure shows relative risk (log scale) comparing children born at each week of gestation with those at 40 weeks of gestation, adjusted for sex, parity, size of gestation, mode of delivery, maternal age, ethnic group, quintile of deprivation and expected month of delivery. KS2 results are adjusted for KS1 attainment: not achieving Level 2 at Key Stage 1 and Level 4 at Key Stage 2. Key Stage 1 refers to the first 2 years of the Educational National Curriculum in England, i.e. Years 1 and 2 (ages 5 to 7). Key Stage 2 refers to Years 3 to 6 (ages 7 to 11)