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Change in smoking status during two consecutive pregnancies: a population‐based cohort study
Author(s) -
Tran DT,
Roberts CL,
Jorm LR,
Seeho S,
Havard A
Publication year - 2014
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/1471-0528.12769
Subject(s) - medicine , pregnancy , odds ratio , confidence interval , obstetrics , population , gestational age , cohort study , logistic regression , cohort , smoking cessation , demography , pediatrics , environmental health , genetics , pathology , sociology , biology
Objective To investigate changes in tobacco smoking in two consecutive pregnancies and factors associated with the change. Design Population‐based cohort study. Setting New S outh W ales, A ustralia, 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.