Summary: | Thesis (M.Sc.)--Memorial University of Newfoundland, 2009. Medicine Includes bibliographical references (leaves 61-77) Objective: To evaluate the effects of second hand smoke exposure in non-smoking pregnant women on perinatal outcomes. -- Methods: This retrospective cohort study included all non-smoking pregnant women with singleton gestations delivering at the Health Sciences Centre, St. John's, Newfoundland and Labrador, from April 1, 2001 to March 31, 2007, who reported whether or not they had been exposed to second hand smoke during pregnancy. Data was drawn from the Newfoundland and Labrador Provincial Perinatal Program Database. The primary outcome was preterm birth less than 37 weeks of gestation. Secondary outcomes included preterm birth less than 34 weeks of gestation, type of labour (spontaneous or induced), and mode of delivery (Caesarean or vaginal delivery), as well as neonatal outcomes including birth weight (including birth weight less than 2,500 g) and admission to the neonatal intensive care unit (NICU). Other outcomes included Apgar scores at one and five minutes, respiratory complications, birth weight over 4,000 g, and use of tocolytics. Univariate analyses and multivariate logistic regression analyses (controlling for potential confounders) were performed and odds ratios (OR) with 95% confidence intervals (CI) were calculated. -- Results: A total of 10,002 women were included in the study - 1,051 with second hand smoke exposure and 8,951 without second hand smoke exposure. Although the rate of preterm birth less than 37 weeks of gestation was not significantly different between the two groups, second hand smoke exposure was independently associated with preterm birth less than 34 weeks of gestation (OR 1.84, 95% CI 1.23 - 2.77, p = 0.003) and low birth weight < 2,500 g (OR 1.75, 95% CI 1.15 - 2.67, p = 0.009). Second hand smoke exposure was also associated with trends towards higher rates of low one minute Apgar score (14.3% compared with 11.8%, p = 0.023), NICU admission (OR 1.24, 95% CI 1.00 - 1.54, p = 0.046), a lower mean birth weight (3,421 +/- 643g compared with 3,505 +/- 612g, p = 0.036), as well as an increased use of endotracheal intubation (3.4% compared with 2.9%), p = 0.062). -- Conclusion: Exposure to second hand smoke during pregnancy can have serious adverse health effects for the pregnant woman and her fetus. Second hand smoke exposure is associated with preterm birth less than 34 weeks of gestation and low birth weight. Continued policy development and education are needed regarding the adverse effects of second hand smoke exposure.
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