Maternal obesity is one of the main public health problems at a world level. It is a multifactorial disease with multiple causes, and few studies exist on its dietary patterns, physical activity and social determinants. This work aims to identify determinants of maternal obesity in a middle income country. Research is based on a prospective cohort design. Data were collected using questionnaires applied to pregnant women. Three dietary patterns were identified, and only half of the women carry out physical activity. The regression analysis showed an association between overweight/obesity and the following variables: age 25 to 29 years old (3.8; CI 1.6-9.0), 30 to 34 years old (3.7; CI 1.2-11.6); health problems during pregnancy (2.1; CI 1.0-4.1); socio-economic income (1.73; CI 1.54-2.05); hypertension (2.7; CI 1.4-4.5); mild food insecurity (1.9; CI 1.0-3.8); moderate insecurity (3.7; CI 0.92-15.4); refined food dietary pattern (.76; CI.61-.95). The risk of increasing BMI during pregnancy mainly depends on socioeconomic and demographic variables such as age, educational level, income, food insecurity, and dietary pattern. This study's results could be used as evidences for the revision, planning, and adjustment of interventions for the prevention and management of maternal obesity, as a part of the national strategies against overweight and obesity.
Keywords: diet; maternal obesity; physical activity; socio-economic indicators.