Monitoring tobacco use during pregnancy is critical for achieving the United Nations Sustainable Development Goals. We examined changes between 2013 and 2019 in the relative differences in smoking prevalence rates between pregnant and non-pregnant women aged 18-49 years. We used data from a nationally representative health survey conducted in Brazil in 2013 and 2019. A generalized linear model with binomial family and logarithmic link function was used to estimate, for each year of analysis, the crude and adjusted (by age-group, educational attainment, place of residence, and status of protection from passive smoking at home) relative differences. In 2013,the proportion point estimate of tobacco use among pregnant women was lower than that observed among non-pregnant women (4.7% vs. 9.6%). However, in 2019 proportion point estimates were virtually the same (8.5% vs. 8.4%). After adjustment for selected variables, in 2013, smoking prevalence among pregnant women was 42% (p-value≤0.05) lower than that observed among non-pregnant women. On the other hand, in 2019, maternal smoking prevalence was 13% (p-value>0.05) higher than that found among non-pregnant women. Ongoing tobacco industry interference and the marketing of tobacco products to vulnerable populations pose serious threats to public health and likely contributed to increasing maternal smoking prevalence. The fact that women smoke in such an important phase of their and their unborn children's lives reinforces the need to strengthen the implementation of concurrent tobacco control actions, including tobacco excise tax policy and pre-natal tobacco prevention and cessation interventions as part of health professionals' routine consultation. The decline in smoking prevalence among non-pregnant women between 2013 and 2019 was accompanied by an increase in maternal smoking prevalence. Monitoring tobacco use during pregnancy is critical for achieving the United Nations Sustainable Development Goals. Ongoing tobacco industry interference and the marketing of tobacco products to vulnerable populations in Brazil pose serious threats to public health. The fact that women smoke in such an important phase of their and their unborn children's lives reinforces the need to strengthen the implementation of concurrent tobacco control actions, including tobacco excise tax policy and primary healthcare professionals´ tobacco-related assistance during interaction with their patients.