Table 1 Odds (95% confidence interval) of being caesarean and other methods of pregnancy delivery, preterm births and high risk pregnancy by IOM, pre-pregnancy BMI categories and gestational weight gain per 0

IOM

Inadequate

0.89

(0.73,1.09)

0.79

(0.64,0.97)

0.79

(0.64,0.98)

0.78

(0.63,0.98)

2.27

(1.71,3.00)

2.41

(1.81,3.20)

0.58

(0.44,0.77)

0.58

(0.44,0.77)

Adequate

1.00

1.00

1.00

1.00

1.00

1.00

1.00

1.00

Excess

1.29

(1.09,1.54)

1.34

(1.12,1.60)

1.25

(1.04,1.49)

1.24

(1.03,1.50)

0.63

(0.44,0.89)

0.53

(0.37,0.76)

2.10

(1.74,2.54)

2.15

(1.78,2.61)

Pre-pregnancy BMI

Underweight

0.95

(0.72,1.26)

0.89

(0.67,1.19)

1.21

(0.94,1.55)

1.28

(0.99,1.65)

1.68

(1.18,2.38)

1.69

(1.19,2.41)

0.64

(0.44,0.93)

0.67

(0.46,0.97)

Normal

1.00

1.00

1.00

1.00

1.00

1.00

1.00

1.00

Overweight

1.40

(1.13,1.75)

1.40

(1.12,1.75)

0.82

(0.63,1.08)

0.79

(0.60,1.04)

0.82

(0.53,1.26)

0.72

(0.46,1.12)

2.15

(1.72,2.69)

2.16

(1.73,2.70)

Obese

2.19

(1.61,2.98)

2.08

(1.51,2.86)

0.77

(0.48,1.25)

0.71

(0.43,1.15)

1.31

(0.74,2.34)

1.08

(0.60,1.95)

3.28

(2.40,4.48)

3.33

(2.43,4.56)

Gestational weight gain (0.1 kg/week)

1.09

(1.03,1.15)

1.10

(1.04,1.16)

1.14

(1.09,1.20)

1.13

(1.07,1.20)

0.84

(0.76,0.92)

0.78

(0.71,0.86)

1.31

(1.24,1.38)

1.32

(1.25,1.40)