Table 3

Crude and adjusted* ORs (95% CI) for adverse perinatal outcomes in pregnant women with and without T1DM and stratified on pre-pregnancy BMI

BMI 18.5–24.9BMI 25–29.9BMI ≥30Interaction p-value†
LGA infant
 T1DM
  Crude10.16 (9.10 to 11.36)12.40 (11.22 to 13.70)12.29 (10.50 to 14.40)<0.001
  Adjusted10.72 (9.56 to 12.01)13.55 (12.23 to 15.02)13.26 (11.27 to 15.59)<0.001
 Non-diabetic
  Crude1.01.74 (1.71 to 1.77)2.52 (2.47 to 2.57)<0.001
  Adjusted1.01.76 (1.73 to 1.79)2.60 (2.55 to 2.66)<0.001
Major malformations
 T1DM
  Crude2.28 (1.71 to 3.04)2.34 (1.81 to 3.02)4.11 (2.99 to 5.65)0.03
  Adjusted2.28 (1.71 to 3.04)2.34 (1.81 to 3.03)4.11 (2.99 to 5.65)0.03
 Non-diabetic
  Crude1.01.10 (1.06 to 1.14)1.15 (1.09 to 1.22)0.03
  Adjusted1.01.10 (1.06 to 1.14)1.15 (1.09 to 1.22)0.03
Pre-eclampsia
 T1DM
  Crude7.12 (6.02 to 8.42)9.30 (8.11 to 10.67)11.23 (9.15 to 13.77)<0.001
  Adjusted7.17 (6.04 to 8.50)9.91 (8.61 to 11.40)14.19 (11.50 to 17.50)<0.001
 Non-diabetic
  Crude1.01.61 (1.56 to 1.66)2.96 (2.86 to 3.07)<0.001
  Adjusted1.01.74 (1.69 to 1.80)3.37 (3.25 to 3.49)<0.001
Preterm delivery
 T1DM
  Crude4.86 (4.22 to 5.60)6.23 (5.53 to 7.02)6.39 (5.30 to 7.71)0.16
  Adjusted4.72 (4.09 to 5.44)5.98 (5.31 to 6.74)5.97 (4.94 to 7.21)0.15
 Non-diabetic
  Crude1.01.05 (1.02 to 1.07)1.28 (1.24 to 1.32)0.16
  Adjusted1.01.04 (1.02 to 1.07)1.26 (1.22 to 1.30)0.15
Perinatal mortality
 T1DM
  Crude2.55 (1.36 to 4.76)3.93 (2.49 to 6.19)3.14 (1.40 to 7.04)0.29
  Adjusted2.46 (1.32 to 4.60)3.72 (2.36 to 5.89)2.86 (1.27 to 6.44)0.31
 Non-diabetic
  Crude1.01.47 (1.35 to 1.59)2.24 (2.04 to 2.46)0.29
  Adjusted1.01.46 (1.35 to 1.59)2.22 (2.03 to 2.44)0.31
Caesarean section
 T1DM
  Crude5.59 (5.00 to 6.25)7.09 (6.42 to 7.83)9.44 (8.04 to 11.08)0.42
  Adjusted5.69 (5.09 to 6.37)7.12 (6.44 to 7.88)9.35 (7.95 to 11.00)0.36
 Non-diabetic
  Crude1.01.33 (1.31 to 1.35)1.84 (1.81 to 1.88)0.42
  Adjusted1.01.34 (1.32 to 1.36)1.87 (1.83 to 1.90)0.36
Neonatal overweight
 T1DM
  Crude8.46 (7.39 to 9.70)9.93 (8.83 to 11.17)11.71 (9.79 to 14.00)<0.001
  Adjusted8.40 (7.32 to 9.64)9.86 (8.76 to 11.11)11.29 (9.42 to 13.53)<0.001
 Non-diabetic
  Crude1.01.66 (1.62 to 1.71)2.59 (2.51 to 2.67)<0.001
  Adjusted1.01.65 (1.61 to 1.69)2.55 (2.48 to 2.63)<0.001

  • Reference group: non-diabetic women with normal pre-pregnancy BMI.

  • ↵* Adjusted for ethnicity, maternal age, height, parity, smoking first trimester and chronic hypertension.

  • ↵† Interaction between BMI category and T1DM.

  • BMI, body mass index; LGA, large for gestational age; T1DM, type 1 diabetes.