Abstract Considering the recent evidence about the negative effect of the consumption of ultra-processed foods (UPF) on current and future generations, and pointing to the development of public food policies adapted to the needs of pregnant women, it is important to identify the factors associated with high consumption of UPF. Cross-sectional comparative study that used data from: 1) a randomized controlled clinical trial conducted with pregnant women treated at Health Units in a city in São Paulo (n = 350), Brazil; and 2) the National Dietary and Physical Activity Survey 2015-2016, Portuguese pregnant women (n = 226). Two 24-hour recall surveys were collected. The UPF were classified according to the Nova. Usual consumption was estimated using the Multiple Source Method software. The percentage of energy coming from UPF was calculated using the mean (±SD) and 95%CI. Adjusted and crude linear regression models were used. The analysis were conducted in SPSS (version 21), considering p < 0.05 as significant. The average age of the total sample was 29.4(±6.3) years and the BMI corresponded to 27.8(±3.4)kg/m². The average daily energy consumption from UPF among Brazilian pregnant women was 449.6(±207.6) kcal, representing 24.2(±8.8)% of the total energy consumed on a usual day; among Portuguese women the average corresponded to 484.2(±242.4)kcal and 22.3(9.3)%, respectively. In crude and adjusted linear regression models, the participation of UPF in total energy was higher among single Brazilian pregnant women compared to married women (3.2[0.8-5.5]p=0.009); Among Portuguese women, an inverse relationship was observed between weekly physical activity (PA) ≥150 minutes and UPF energy consumption (-3.2[-6.0 - -0.3]p= 0, 03). In the studied pregnant women, results showed that being single and practicing less than 150 minutes of PA weekly were factors associated with greater consumption of UPF, characterizing a priority group to receive nutritional interventions during prenatal care. Key messages • Public policies and strategies to reduce the consumption of ultra-processed foods during pregnancy. • Promotion of healthy lifestyle habits and impact on current and future health.