Table 2 Association of adverse neonatal outcomes with low and high birthweights after GROW, INTERGROWTH and WHO criteria. Relative risk ratios and 95% confidence intervals are reported in comparison to all other pregnancies. Neonatal hypoglycaemia included only infants who required IV dextrose. GROW: gestation related optimum weight; NICU: neonatal intensive care unit; WHO: world health organisation. Composite outcome: birth injury, neonatal hypoglycaemia, hyperbilirubinaemia, respiratory distress syndrome, or neonatal intensive care admission. * p< 0.05; **p< 0.01; ***p< 0.001

 GROW > 84.1st centile

146/225 (64.9%)

1.66 (0.97 to 2.84)

1.41 (0.95 to 2.10)

1.56 (0.94 to 2.56)

2.03 (0.70 to 5.91)

1.46 (1.05 to 2.02)*

 INTERGROWTH > 84.1st centile

167/225 (74.2%)

1.45 (0.81 to 2.61)

1.17 (0.77 to 1.77)

1.19 (0.71 to 1.99)

1.30 (0.45 to 3.77)

1.20 (0.85 to 1.69)

 WHO > 84.1st centile

82/225 (36.4%)

1.36 (0.87 to 2.13)

0.99 (0.69 to 1.41)

0.77 (0.48 to 1.23)

0.80 (0.32 to 2.04)

1.00 (0.75 to 1.33)

 GROW >90th centile

140/225 (62.2%)

1.86 (1.09 to 3.20)*

1.49 (1.01 to 2.21)*

1.61 (0.99 to 2.62)

2.28 (0.78 to 6.63)

1.56 (1.13 to 2.16)**

 INTERGROWTH >90th centile

150/225 (66.7%)

1.69 (0.97 to 2.94)

1.48 (0.98 to 2.22)

1.44 (0.87 to 2.36)

1.88 (0.64 to 5.45)

1.41 (1.01 to 1.96)*

 WHO >90th centile

67/225 (29.8%)

1.48 (0.94 to 2.33)

1.02 (0.70 to 1.47)

0.82 (0.50 to 1.34)

0.63 (0.22 to 1.82)

1.05 (0.78 to 1.41)

 GROW > 97.7th centile

95/225 (42.2%)

2.35 (1.47 to 3.75)***

1.62 (1.15 to 2.28)**

1.56 (1.02 to 2.38)*

1.88 (0.79 to 4.50)

1.50 (1.14 to 1.97)**

 INTERGROWTH > 97.7th centile

92/225 (40.9%)

2.30 (1.45 to 3.65)***

1.48 (1.06 to 2.08)*

1.19 (0.78 to 1.82)

1.61 (0.68 to 3.80)

1.42 (1.08 to 1.86)*

 WHO > 97.7th centile

28/225 (12.4%)

2.29 (1.45 to 3.61)***

1.55 (1.05 to 2.30)*

0.90 (0.45 to 1.77)

1.32 (0.41 to 4.24)

1.33 (0.95 to 1.86)

 GROW <10th centile

5/225 (2.2%)

0.79 (0.13 to 4.60)

1.65 (0.79 to 3.45)

2.24 (1.06 to 4.73)*

2.44 (0.40 to 14.91)

1.27 (0.61 to 2.63)

 INTERGROWTH <10th centile

3/225 (1.3%)

Insufficient events

1.83 (0.81 to 4.14)

2.47 (1.08 to 5.65)*

4.11 (0.78 to 21.63)

1.41 (0.63 to 3.18)

 WHO <10th centile

20/225 (8.9%)

1.21 (0.59 to 2.45)

1.90 (1.31 to 2.77)***

1.74 (1.02 to 2.98)*

3.66 (1.47 to 9.11)**

1.67 (1.24 to 2.24)***

 GROW <25th centile

13/225 (5.8%)

0.59 (0.16 to 2.17)

1.05 (0.51 to 2.13)

1.43 (0.69 to 2.95)

1.92 (0.50 to 7.43)

0.80 (0.40 to 1.61)

 INTERGROWTH <25th centile

7/225 (3.1%)

0.56 (0.09 to 3.46)

1.58 (0.81 to 3.07)

2.15 (1.09 to 4.23)*

3.66 (1.04 to 12.88)*

1.21 (0.63 to 2.33)

 WHO <25th centile

37/225 (16.4%)

1.22 (0.70 to 2.12)

1.83 (1.31 to 2.57)***

1.77 (1.13 to 2.76)*

2.96 (1.25 to 7.02)*

1.22 (0.70 to 2.12)