Expected and observed percentage (n) below selected centiles: very preterm, late-to-moderate preterm, term: MBRRACE-UK vs UK-WHO (females)
| Expected* | Very preterm (<32 weeks) (n=2230) | Late-to-moderate preterm (32–36 weeks) (n=14 425) | Term (>36 weeks) (n=296 106) | ||||||
| Observed % (n) MBRRACE-UK | Observed % (n) UK-WHO | Risk difference† (95% CI) | Observed % (n) MBRRACE-UK | Observed % (n) UK-WHO | Risk difference† (95% CI) | Observed % (n) MBRRACE-UK | Observed % (n) UK-WHO | Risk difference† (95% CI) | |
| Below 0.4th (0.38%) | 0.85 (19) | 1.21 (27) | 0.36 (−0.23 to 0.95) | 0.76 (109) | 0.55 (80) | −0.20 (−0.39 to −0.01) | 0.40 (1193) | 0.28 (832) | −0.12 (−0.15 to −0.09) |
| Below 2nd (2.28%) | 2.78 (62) | 3.54 (79) | 0.76 (−0.26 to 1.79) | 2.83 (408) | 2.31 (333) | −0.52 (−0.88 to −0.15) | 1.98 (5860) | 1.44 (4274) | −0.54 (−0.60 to −0.47) |
| Below 9th (9.13%) | 7.85 (175) | 10.90 (243) | 3.05 (0.13 to 4.76) | 8.89 (1282) | 7.83 (1129) | −1.06 (−1.70 to −0.42) | 8.04 (23 809) | 6.43 (19 037) | −1.61 (−1.74 to −1.48) |
| Below 25th (25.24%) | 22.06 (492) | 25.52 (569) | 3.45 (0.96 to 5.95) | 22.90 (3304) | 20.28 (2925) | −2.62 (−3.58 to −1.68) | 23.70 (70 182) | 20.33 (60 190) | −3.37 (−3.59 to −3.16) |
| Below 50th (50%) | 44.57 (994) | 46.59 (1039) | 2.02 (−0.90 to 4.94) | 49.29 (7110) | 43.40 (6260) | −5.89 (−7.04 to −4.74) | 48.97 (144 996) | 44.66 (132 244) | −4.31 (−4.56 to −4.05) |
| Below 75th (74.76%) | 76.19 (1699) | 74.04 (1651) | −2.15 (−4.69 to 0.38) | 77.64 (11 199) | 70.29 (10 140) | −7.34 (−8.35 to −6.33) | 74.43 (220 379) | 71.57 (211 917) | −2.86 (−3.08 to −2.63) |
| Below 91st (90.87%) | 92.91 (2072) | 90.58 (2020) | −2.33 (−3.95 to −0.72) | 92.00 (13 271) | 87.36 (12 601) | −4.64 (−5.34 to −3.94) | 90.74 (268 673) | 89.21 (264 147) | −1.53 (−1.68 to −1.38) |
| Below 98th (97.72%) | 96.64 (2155) | 95.56 (2131) | −1.08 (−2.21 to −0.06) | 96.80 (13 964) | 94.52 (13 634) | −2.29 (−2.76 to −1.82) | 97.53 (288 778) | 96.99 (287 200) | −0.53 (−0.62 to −0.45) |
| Below 99.6th (99.62%) | 97.58 (2176) | 96.86 (2160) | −0.72 (−1.68 to 0.25) | 98.74 (14 243) | 97.40 (14 050) | −1.34 (−1.66 to −1.02) | 99.46 (294 501) | 99.30 (294 045) | −0.15 (−0.19 to −0.11) |
*Centiles and expected percentages based on 0.67 SD score spacing between centiles.8
†Risk difference=prevalence below a given centile according to UK-WHO minus prevalence according to MBRRACE-UK.