Light and Heavy Smoking During Pregnancy: Prevalence and Associations with Perinatal Risk Factors and Birth Outcomes, Maryland, 2001-2006

Background: Smoking during pregnancy has been established as a risk factor for poor birth outcomes including preterm birth and low birth weight. The goal of this analysis was to understand the prevalence and perinatal risk factors of light and heavy smoking during pregnancy among Maryland women.

Methods: Data were obtained from a stratified random sample of 9225 mothers who delivered live infants during the years 2001-2006 and completed the Maryland Pregnancy Risk Assessment Monitoring System (PRAMS) survey. Descriptive and bivariate analyses were performed using SUDAAN. Smoking during pregnancy was based on the number of cigarettes smoked daily during the last 3 months of pregnancy.

Results: In Maryland, of the 9.5% of mothers who reported smoking during pregnancy, 4.5% smoked <= cigarettes/day (lighter smokers), and 5.0% smoked >5 cigarettes/day (heavier smokers). Smoking was most prevalent among white non-Hispanics and mothers <25 years of age.

Smokers were less likely than non-smokers to take pre-pregnancy folic acid daily (Heavier: 11.9%, Lighter: 21.7%, Non: 32.4%), more likely to report an unintended pregnancy (Heavier: 62.4%, Lighter: 49.7%, Non: 39.6%), and also more likely to receive late or no prenatal care (Heavier: 34.3%, Lighter: 28.3%, Non: 22.2%).

Smokers had higher percentages of low weight (<2500g) births (Heavier: 15.1%, Lighter: 11.3%, Non: 7.4%) and preterm births (<37 weeks) than nonsmokers (Heavier: 14.3%, Lighter: 11.4%, Non: 9.4%).

Discussion: This analysis indicates that both light and heavy smoking during pregnancy is associated with perinatal risk factors and poor birth outcomes.