Trends and Variations in Smoking During Pregnancy and Low Birth Weight: Evidence From the Birth Certificate, 1990–2000

OBJECTIVE: This study compares patterns of tobacco use during pregnancy over time and across population subgroups and examines the impact of maternal smoking on the incidence of low birth weight (LBW). The study also evaluates the use of birth certificates to monitor prenatal smoking. METHODS: The birth certificates of all states (except California) and the District of Columbia for 2000 provided to Centers for Disease Control and Prevention's National Center for Health Statistics were analyzed. Trends in maternal smoking were examined with data from birth certificates and other relevant sources. RESULTS: Smoking during pregnancy was reported for 12.2% of women who gave birth in 2000, down 37% from 1989 (19.5%), when this information was first collected on birth certificates. Throughout the 1990s, prenatal smoking rates were highest for older teenagers and women in their early 20s. Among population subgroups, the highest rates were reported for non-Hispanic white women who attended but did not complete high school. The incidence of LBW among singleton infants who were born to smokers was double that for nonsmokers. This relationship was observed in all age groups, for births to Hispanic and non-Hispanic white and black women, and within educational attainment subgroups. Even light smoking (<5 cigarettes daily) was associated with elevated rates of LBW. CONCLUSION: Although prenatal smoking may be underreported on the birth certificate, the trends and variations in smoking based on birth certificate data have been confirmed with data from other sources. Birth certificate data can be useful in monitoring prenatal smoking patterns. Changes in the birth certificate questions that are to be implemented beginning in 2003 will help to clarify the levels and changes in smoking behavior during pregnancy so that smoking cessation programs can be more effectively designed to meet the needs of the populations at risk.