Heavy smoking during pregnancy as a marker for other risk factors of adverse birth outcomes: a population-based study in British Columbia, Canada
Date
2012-02-06
Authors
Erickson, Anders C
Arbour, Laura T
Journal Title
Journal ISSN
Volume Title
Publisher
BioMed Central
Abstract
Abstract
Background: Smoking during pregnancy is associated with known adverse perinatal and obstetrical outcomes as
well as with socio-economic, demographic and other behavioural risk factors that independently influence
outcomes. Using a large population-based perinatal registry, we assess the quantity of cigarettes smoked for the
magnitude of adverse birth outcomes and also the association of other socio-economic and behavioural risk
factors documented within the registry that influence pregnancy outcomes. Our goal was to determine whether
number of cigarettes smoked could identify those in greatest need for comprehensive intervention programs to
improve outcomes.
Methods: Our population-based retrospective study of singleton births from 2001 to 2006 (N = 237,470) utilized
data obtained from the BC Perinatal Database Registry. Smoking data, self reported at the earliest prenatal visit, was
categorized as: never, former, light (1 to 4), moderate (5 to 9), or heavy smoker (10 or more per day). Crude and
adjusted odds ratios (AOR) with 95% confidence intervals (95% CI) were calculated using logistic regression models
for smoking frequency and adverse birth outcomes. A partial proportional odds (pp-odds) model was used to
determine the association between smoking status and other risk factors.
Results: There were 233,891 singleton births with available smoking status data. A significant dose-dependent
increase in risk was observed for the adverse birth outcomes small-for-gestational age, term low birth weight and
intra-uterine growth restriction. Results from the pp-odds model indicate heavy smokers were more likely to have
not graduated high school: AOR (95% CI) = 3.80 (3.41-4.25); be a single parent: 2.27 (2.14-2.42); have indication of
drug or alcohol use: 7.65 (6.99-8.39) and 2.20 (1.88-2.59) respectively, attend fewer than 4 prenatal care visits: 1.39
(1.23-1.58), and be multiparous: 1.59 (1.51-1.68) compared to light, moderate and non-smokers combined.
Conclusion: Our data suggests that self reports of heavy smoking early in pregnancy could be used as a marker
for lifestyle risk factors that in combination with smoking influence birth outcomes. This information may be used
for planning targeted intervention programs for not only smoking cessation, but potentially other support services
such as nutrition and healthy pregnancy education.
Description
BioMed Central
Keywords
Citation
Erickson, A., & Arbour, L. (2012). Heavy smoking during pregnancy as a marker for other risk factors of adverse birth outcomes: A population-based study in British Columbia, Canada. BMC Public Health, 12, 102