Context: Rates of smoking are increasing among adolescents and young adults, but trends in smoking among pregnant women have not been studied.
Objective: To assess pregnancy-related variations in smoking behaviors and their determinants among women of childbearing age in the United States.
Design: Analysis of data collected between 1987-1996 from the Behavioral Risk Factor Surveillance System survey.
Setting and subjects: A total of 187302 (178499 nonpregnant and 8803 pregnant) noninstitutionalized women aged 18 to 44 years from 33 states.
Main outcome measures: Prevalence rates of smoking initiation and current smoking, median number of cigarettes smoked, and adjusted odds ratios for smoking stratified by pregnancy status; prevalence rate ratio for current smoking comparing pregnant with nonpregnant women.
Results: The overall percentage of women who had ever initiated smoking decreased significantly from 44.1% in 1987 to 38.2% in 1996. During that 10-year period, the prevalence of current smoking also decreased significantly among both pregnant women (16.3% to 11.8%) and nonpregnant women (26.7% to 23.6%). Overall, pregnant women were about half (54%) as likely as nonpregnant women to be current smokers during 1987-1996. Over time, the median number of cigarettes smoked per day by pregnant smokers remained at 10, whereas among nonpregnant smokers it decreased from 19 to 15 (P<.05 for trend). In the same period, among young women (aged 18-20 years), prevalence rates of smoking initiation and current smoking increased slightly. Sociodemographic subgroups of women at increased risk for current smoking were the same for pregnant and nonpregnant women (ie, those with a completed high school education or less, whites, and those who were unmarried).
Conclusions: In this analysis, the decline in smoking over time among pregnant women was primarily due to the overall decline in smoking initiation rates among women of childbearing age, not to an increased rate of smoking cessation related to pregnancy. To foster effective perinatal tobacco control, efforts are needed to further reduce the number of young women who begin smoking. Clinicians should query all pregnant women and women of childbearing age about smoking and provide cessation and relapse interventions to each smoker.