Introduction: Maternal smoking during pregnancy is a major modifiable risk factor for maternal and fetal morbidity. Few studies have specifically examined the characteristics of women who reduced their smoking during pregnancy but were unable to quit completely. The objectives were to describe the factors associated with smoking cessation and reduction behaviors during pregnancy and their regional disparities. Method: The analyses are based on data from the 2016 National Perinatal Survey (ENP). This is a representative sample of births for that year. The study population consisted of 12,399 adult women who gave birth to a live infant (including 652 in the overseas departments and regions). Characteristics associated with a reduction in tobacco use (less than 50%: R<50% or greater than 50%: R≥50%) compared to quitting were analyzed using multinomial logistic regression among smokers. Results: In 2016, 30.0% of women smoked before pregnancy. Among them, 45.8% quit smoking before the third trimester, 37.2% halved their consumption (R≥50%), and 16.9% reduced their consumption only slightly (R<50%). 16.2% were smoking in the third trimester. These proportions varied according to the number of cigarettes smoked before pregnancy. Sociodemographic characteristics were less favorable for women who reduced their consumption only slightly during pregnancy, and multiparity was associated with a reduction in smoking rather than cessation. Regional disparities were observed. Conclusion: sociodemographic context, the number of cigarettes smoked before pregnancy, and region appear to be important factors to consider when identifying women at highest risk of continuing to smoke during pregnancy.