OBJECTIVE: To examine the effect of cigarette smoking during pregnancy on the development of preterm premature rupture of membranes (PPROM) categorized by gestational age. METHODS: We conducted a retrospective cohort study of 17,961 births using data from the McGill Obstetric and Neonatal Database between years 2001 and 2006. Our exposure was defined according to self-reported maternal cigarette smoking status categorized as nonsmoker, smoker of 1 to 10 cigarettes per day, and smoker of > 10 cigarettes per day. The outcome was measured as incidence of premature rupture of membranes (PROM) among gestational age categories of < 28, < 32, < 37, and > 37 weeks. Unconditional logistic regression analysis and Wald test for trend were used to estimate the adjusted risk of PPROM according to smoking status. RESULTS: Among the study population, 640 cases of PPROM (<37 weeks) and 40 cases of PROM (>37 weeks). After adjusting for confounding variables, smoking > 10 cigarettes per day was associated with an increased risk of PPROM at < 28 weeks (odds ratio [OR] 5.28; 95% confidence interval [CI] 2.20 to 12.7); < 32 weeks (OR 2.36; 95% CI 1.09 to 5.11; < 37 weeks (OR 1.97; 95% CI 1.32 to 2.94); and > 37 weeks (OR 3.19; 95% CI 0.92 to 11.0). Smoking 1 to 10 cigarettes per day was not associated with a significant risk of PPROM at any gestational age. CONCLUSION: Heavy cigarette smoking increases the risk of PPROM more so at early gestational age than at term.
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England et al. (2013) studied this question.