Table 2.
Perinatal outcomes of women by objectively measured smoking status, time and legislative changes to the Tobacco Act
| Outcome | Non-smokers (N=6892) (reference category) | Women who undisclosed smoking (N=745) |
Inactive cigarette smokers (N=431) |
Active cigarette smokers (N=1559) |
|||
|---|---|---|---|---|---|---|---|
| % | % | OR (95% CI) | % | OR (95% CI) | % | OR (95% CI) | |
| Preterm birth <37 weeks' gestation | |||||||
| 1987–1993 | 4.8 | 7.4 | 1.59 (1.04 to 2.44) | 10.4 | 2.30 (1.27 to 4.17) | 7.6 | 1.64 (1.17 to 2.30) |
| 1994–2003 | 7.4 | 11.3 | 1.59 (1.06 to 2.39) | 9.2 | 1.27 (0.76 to 2.11) | 10.7 | 1.51 (1.14 to 2.00) |
| 2004–2011 | 6.1 | 9.4 | 1.61 (0.80 to 3.23) | 9.4 | 1.64 (0.79 to 3.40) | 7.6 | 1.28 (0.75 to 2.17) |
| Perinatal deaths | |||||||
| 1987–1993 | 0.4 | 0.3 | 0.86 (0.11 to 6.94) | 2.9 | 5.26 (0.93 to 29.65) | 0.9 | 2.57 (0.93 to 7.11) |
| 1994–2003 | 0.6 | 1.1 | 1.73 (0.51 to 5.89) | 1.8 | 2.72 (0.79 to 9.33) | 0.6 | 0.94 (0.32 to 2.76) |
| 2004–2011 | 1.4 | 1.9 | 1.38 (0.31 to 6.10) | 1.0 | 0.74 (0.10 to 5.64) | 1.6 | 1.17 (0.38 to 3.55) |
| Child hospitalised during early neonatal period | |||||||
| 1987–1993 | 4.5 | 6.4 | 1.44 (0.90 to 2.29) | 8.7 | 1.97 (0.82 to 4.75) | 5.3 | 1.19 (0.80 to 1.75) |
| 1994–2003 | 5.6 | 6.6 | 1.18 (0.71 to 1.98) | 7.3 | 1.33 (0.75 to 2.37) | 9.1 | 1.68 (1.24 to 2.29) |
| 2004–2011 | 4.4 | 8.7 | 2.06 (0.98 to 4.33) | 4.5 | 1.03 (0.36 to 2.91) | 6.5 | 1.52 (0.85 to 2.72) |
| Caesarean delivery | |||||||
| 1987–1993 | 15.6 | 14.2 | 0.89 (0.65 to 1.22) | 14.4 | 0.90 (0.53 to 1.53) | 15.0 | 0.95 (0.75 to 1.21) |
| 1994–2003 | 22.0 | 19.9 | 0.88 (0.64 to 1.20) | 23.8 | 1.11 (0.78 to 1.56) | 20.8 | 0.93 (0.76 to 1.15) |
| 2004–2011 | 17.1 | 10.4 | 0.56 (0.30 to 1.07) | 16.3 | 0.95 (0.54 to 1.66) | 16.1 | 0.93 (0.64 to 1.35) |
The ORs with 95% CIs are obtained from binomial logistic regression, where we modelled the effect of objectively smoking status, time and the interaction between objectively measured smoking status and time.