Author(s): Tran DT, Roberts CL, Jorm LR, Seeho S, Havard A
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Abstract OBJECTIVE: To investigate changes in tobacco smoking in two consecutive pregnancies and factors associated with the change. DESIGN: Population-based cohort study. SETTING: New South Wales, Australia, 2000-10. POPULATION: A total of 183,385 women having first and second singleton pregnancies. METHODS: Descriptive and multivariable logistic regression analyses of perinatal data linked to hospital admission data. MAIN OUTCOME MEASURES: Proportion of women smoking during their first pregnancy who quit by their second, and of women not smoking in their first pregnancy who did smoke during their second. RESULTS: Among 22,761 smokers in the first pregnancy, 33.5\% had quit by their second. Among 160,624 non-smokers in their first pregnancy, 3.6\% smoked during their second. Women who were aged ≥25 years, were married, born in a non-English speaking country, used private obstetric care, and lived in a socio-economically advantaged area were more likely to quit or less likely to start smoking in the second pregnancy. Smokers who had gestational hypertension (adjusted odds ratio [OR] 1.36, 95\% confidence interval [95\% CI] 1.23-1.51), a large-for-gestational-age infant (OR 1.66, 95\% CI, 1.46-1.89), and a stillbirth (OR 1.44, 95\% CI 1.06-1.94) were more likely to quit, whereas smokers whose infant was small-for-gestational-age (OR 0.65, 95\% CI 0.60-0.70) or admitted to special care nursery (OR 0.87, 95\% CI 0.81-0.94) were less likely to quit. Among non-smokers in the first pregnancy, the risk of smoking in the second pregnancy increased with late antenatal attendance (e.g. ≥26 weeks, OR 1.30, 95\% CI 1.14-1.48), gestational diabetes (OR 1.25, 95\% CI 1.07-1.45), preterm birth (e.g. spontaneous, OR 1.25, 95\% CI 1.10-1.43), caesarean section (e.g. prelabour, OR 1.13, 95\% CI 1.01-1.26), and infant small-for-gestational-age (OR 1.37, 95\% CI 1.26-1.48) or required special care nursery (OR 1.14, 95\% CI 1.06-1.23). Inter-pregnancy interval of ≥3 years was associated with either change in smoking status. CONCLUSIONS: Most smokers continue to smoke in their next pregnancy, even among those who experienced poor outcomes. Intensive interventions should be explored and offered to women at the highest risk. © 2014 Royal College of Obstetricians and Gynaecologists.
This article was published in BJOG
and referenced in Journal of Pregnancy and Child Health