[Smoking during pregnancy in France between 1972 to 2003: Results from the national perinatal surveys]

To study trends in smoking before and during pregnancy in national samples of pregnant women and changes in characteristics of smokers over time, and describe the current relation between maternal smoking during pregnancy and fetal growth.Five nationally representative samples of singleton live births in metropolitan France (1972, 1981, 1995, 1998 and 2003) were used to study the change in smoking rates during pregnancy over the past 30 years. We further examined changes in smoking rates between 1998 and 2003 according to maternal characteristics. Finally, we estimated the effect of smoking on fetal growth in 2003.Prevalence of smoking decreased over time, but the rate remained high, 21 % in 2003. The decrease was more important among women at low risk of adverse pregnancy outcomes, resulting in increased social disparities. We confirmed the strong dose-response relation between tobacco use during pregnancy and fetal growth.It is important to verify that smoking during pregnancy is still decreasing and to develop policies to encourage women to quit smoking during pregnancy, especially for highly exposed groups.