Table 5 Associations of the intensity of maternal cigarette smoking in the second trimester with birth congenital anomalies

Congenital diaphragmatic hernia

 n (/10000)

1327 (1.16)

49 (1.79)

58 (1.88)

33 (2.35)

 RR (95% CI)

1.00

1.32 (0.98–1.76)

1.29 (0.98–1.70)

1.56 (1.09–2.22)

 P value

0.0661

0.0660

0.0144

Gastroschisis

 n (/10000)

2332 (2.04)

156 (5.69)

163 (5.27)

69 (4.91)

 RR (95% CI)

1.00

1.50 (1.27–1.77)

1.37 (1.16–1.61)

1.30 (1.02–1.67)

 P value

< 0.0001

0.0002

0.0335

Limb reduction defect

 n (/10000)

1468 (1.29)

60 (2.19)

84 (2.72)

43 (3.06)

 RR (95% CI)

1.00

1.32 (1.01–1.71)

1.56 (1.24–1.96)

1.69 (1.24–2.31)

 P value

0.0419

0.0002

0.0010

Cleft lip with or without cleft palate

 n (/10000)

5747 (5.03)

206 (7.51)

261 (8.44)

130 (9.25)

 RR (95% CI)

1.00

1.22 (1.06–1.41)

1.26 (1.10–1.43)

1.33 (1.11–1.59)

 P value

0.0062

0.0005

0.0016

Cleft palate alone

 n (/10000)

2624 (2.3)

105 (3.83)

166 (5.37)

71 (5.05)

 RR (95% CI)

1.00

1.28 (1.05–1.57)

1.63 (1.38–1.92)

1.50 (1.18–1.91)

 P value

0.0143

< 0.0001

0.0011

Any outcome*

 n (/10000)

12981 (11.37)

558 (20.34)

696 (22.51)

328 (23.35)

 RR (95% CI)

1.00

1.32 (1.21–1.44)

1.36 (1.26–1.47)

1.38 (1.23–1.54)

 P value

< 0.0001

< 0.0001

< 0.0001