Table 2 Maternal risk factors during pregnancy for Crohn’s disease (CD) and ulcerative colitis (UC) by logistic regression

Smoking

n

n

no (ref) (n = 5 967)

34

100

1–10 cigarettes (n = 582)

4 1.21 (0.43–3.41)

11 1.17 (0.62–2.19)

1.44 (0.50–4.15)

1.20 (0.62–2.33)

> 10 cigarettes (n = 103)

3 5.23 (1.58–17.3)

2 1.20 (0.29–4.93)

5.78 (1.70–19.7)

1.36 (0.33–5.62)

Antibiotic use

n

n

no (ref) (n = 5727)

28

96

yes (n=609)

9 3.05 (1.43–6.50)

8 0.88 (0.44–1.75)

2.33 (0.95–5.72)

0.91 (0.44–1.89)