Table 5

Crude and aORs for the association between BMI and each adverse pregnancy outcome

OutcomesPer cent*Crude OR (95% CI)p ValueaOR (95% CI)p Value
PTB (n=6200)
 <18.515.131.16 (1.08 to 1.24)<0.00011.16 (1.08 to 1.25)<0.0001
 18.5–23.973.24RefRef
 24–27.99.481.03 (0.94 to 1.12)0.56201.01(0.92 to 1.10)0.8940
 ≥282.151.21 (1.02 to 1.44)0.02901.18 (0.99 to 1.4)0.0640
LBW (n=1909)
 <18.519.751.64 (1.46 to 1.84)<0.00011.57 (1.4 to 1.77)<0.0001
 18.5–23.967.26RefRef
 24–27.910.371.22 (1.05 to 1.42)0.00901.22 (1.05 to 1.42)0.0110
 ≥282.621.61 (1.22 to 2.14)<0.00011.60 (1.2 to 2.12)0.0010
SM (n=15 437)
 <18.513.961.07 (1.02 to 1.13)0.00301.11 (1.06 to 1.17)<0.0001
 18.5–23.972.79RefRef
 24–27.910.851.18 (1.12 to 1.24)<0.00011.02 (0.97 to 1.08)0.3680
 ≥282.41.37 (1.23 to 1.52)<0.00011.13 (1.02 to 1.26)0.0210
EP (n=441)
 <18.512.700.96 (0.73 to 1.28)0.80301.09 (0.82 to 1.45)0.5620
 18.5–23.973.70RefRef
 24–27.99.070.98 (0.70 to 1.35)0.88000.74 (0.53 to 1.04)0.0810
 ≥284.542.55 (1.62 to 4.01)<0.00011.78 (1.13 to 2.81)0.0130
SB (n=1332)
 <18.512.841.00 (0.85 to 1.17)0.98201.05 (0.89 to 1.24)0.5400
 18.5–23.972.00RefRef
 24–27.911.761.30 (1.10 to 1.54)0.00901.13 (0.95 to 1.34)0.1640
 ≥283.381.94 (1.44 to 2.62)<0.00011.59 (1.18 to 2.15)0.0030
  • *Proportions of each adverse pregnancy outcome among four BMI categories.

  • aOR, adjusted OR; BMI, body mass index; EP, ectopic pregnancy; LBW, low-birth-weight; PTB, preterm birth; SB, stillbirth; SM, spontaneous miscarriage.