Prevalence of smoking associated with pregnancy in three Southern Ontario Health Units.

Objectives: The objectives of this study were to determine the prevalence of pregnancy-associated smoking among women residing in three Southern Ontario Health Units and to examine potential risk factors for smoking during pregnancy, using an existing data collection mechanism.

Methods: During May 2001, questions about pregnancy-associated smoking were asked during the telephone follow-up of postpartum women living in the three health units in Southern Ontario; this follow-up is routinely conducted by public health nurses. Sociodemographic data were also obtained. Data from 1,134 women were analyzed concerning smoking before and after the occurrence of the pregnancy was known, during each trimester, and immediately postpartum.

Results: The rates of smoking before and after the pregnancy was known, in the first, second, and third trimesters, and immediately postpartum were 17.8%, 10.4%, 9.6%, 8.7%, 8.1%, and 7.9%, respectively. For all six estimates of smoking, Canadian-born women had rates 2.5 to 4 times higher than those of women born outside Canada. Age less than 25 years and lower educational attainment were also independent risk factors for smoking during pregnancy.

Conclusions: The Ontario Tobacco Strategy goal of eliminating smoking in pregnancy has not yet been realized. Ongoing smoking cessation programs among pregnant women are needed as part of a comprehensive strategy to reduce the overall prevalence of smoking. In planning such programs, particular attention should be paid to the needs of women who are Canadian-born, have lower educational attainment, and are under the age of 25.