Table 4 Adjusted population attributable fractions (PAFs) of adverse neonatal outcomes due to BMI, GWG and prenatal smoking*

All women (n = 71,200)

Underweight

6.0

2.6 [2.5, 2.7]

5.3 [5.2, 5.4]

−1.4 [-1.4, -1.3]

Overweight

20.9

−0.4 [-0.6, -0.2]

−0.8 [-0.9, -0.7]

6.5 [6.3, 6.6]

Obese

13.5

0.3 [0.1, 0.4]

−1.6 [-1.7, -1.5]

8.9 [8.8, 9.1]

< recommended GWG

18.6

4.7 [4.4, 5.0]

9.2 [9.0, 9.4]

−6.3 [-6.4, -6.2]

> recommended GWG

59.4

18.2 [17.8, 18.7]

−16.3 [-16.4, -16.1]

15.9 [15.4, 16.3]

Smoked 3^rd trimester

10.4

3.2 [3.0, 3.3]

8.7 [8.6, 8.8]

−7.1 [-7.2, -7.0]

Primigravidas (n = 24,000)

Underweight

7.1

3.3 [3.1, 3.5]

7.5 [7.4, 7.7]

−4.6 [-4.7, -4.5]

Overweight

17.6

4.8 [4.5, 5.1]

−1.4 [-1.6, -1.3]

2.0 [1.7, 2.2]

Obese

12.0

−1.7 [-2.0, -1.5]

−0.1 [-0.2, 0.1]

8.9 [8.6, 9.1]

< recommended GWG

16.6

5.7 [5.5, 6.0]

6.1 [5.8, 6.5]

−5.1 [-5.3, -4.9]

> recommended GWG

61.3

33.9 [33.1, 34.6]

−22.8 [-23.4, -22.3]

37.9 [37.1, 38.6]

Smoked 3^rd trimester

7.7

0.3 [0.1, 0.5]

7.5 [7.4, 7.6]

−5.1 [-5.2, -5.0]

Multigravidas, previous PTB (n = 4,000)

Underweight

6.2

−1.4 [-1.6 ,-1.2]

4.6 [4.2, 5.1]

--^a

Overweight

22.9

−10.5 [-11.1, -9.9]

1.9 [1.3, 2.5]

--^a

Obese

19.6

−2.1 [-2.6, -1.7]

−14.0 [-14.9,-13.2]

--^a

< recommended GWG

18.0

−3.0 [-3.6, -2.4]

8.0 [7.1, 8.9]

--^a

> recommended GWG

58.7

−3.6 [-5.1, -2.1]

−54.8 [-57.1, -52.4]

--^a

Smoked in 3^rd trimester

17.2

5.4 [4.9, 6.0]

9.7 [9.0, 10.4]

--^a

Multigravidas, no previous PTB, previous loss^b (n = 21,300)

Underweight

5.3

3.5 [3.3, 3.7]

3.2 [3.1, 3.4]

0.1 [0.0, 0.2]

Overweight

23.1

−0.05 [-0.4, 0.3]

−5.6 [-5.9, -5.4]

8.9 [8.6, 9.2]

Obese

13.5

−1.2 [-1.4, -0.9]

−2.2 [-2.4, -2.0]

13.0 [12.7, 13.2]

< recommended GWG

19.4

2.7 [2.3, 3.1]

11.0 [10.6, 11.4]

−11.4 [-11.6, -11.1]

> recommended GWG

58.3

−3.7 [-4.5, -2.8]

−8.6 [-9.3, -7.9]

1.1 [0.2, 1.9]

Smoked 3^rd trimester

13.7

8.0 [7.7, 8.2]

13.0 [12.7, 13.2]

−13.2 [-13.4,-13.0]

Multigravidas, no previous PTB, no previous loss^b (n = 21,600)

Underweight

5.4

4.2 [4.0, 4.5]

3.8 [3.7, 4.0]

−0.2 [-0.3, -0.1]

Overweight

22.3

−5.9 [-6.4, -5.5]

3.9 [3.6, 4.2]

7.6 [7.4, 7.8]

Obese

13.9

3.4 [3.0, 3.8]

−2.5 [-2.7, -2.3]

7.9 [7.7, 8.1]

< recommended GWG

20.2

9.5 [9.1, 9.9]

12.3 [11.6, 13.1]

−5.0 [-5.2, -4.8]

> recommended GWG

54.9

38.7 [37.8, 39.5]

−9.3 [-10.0, -8.6]

15.2 [14.6, 15.8]

Smoked 3^rd trimester

9.0

1.6 [1.2, 1.9]

7.0 [6.8, 7.2]

−5.4 [-5.4, -5.3]