Secular trend for overweight and excessive weight gain during pregnancy in a SouthernChilean regionBackground: Overweight during pregnancy has increased in Chile. In the region of La Araucanía it occurs in 67% of pregnancies, which exceeds the national indicators. Aim: To analyze the secular trend during eight years of the nutritional status at the beginning of gestation, the excessive weight gain during pregnancy, and its association with individual factors in pregnant women cared the public health system of two Southern Chilean neighboring cities. Material and Methods: This is an analytical observational study with a cross-sectional and longitudinal trend design. We used an anonymized database with 17,270 reproductive data of urban pregnant women who were cared between 2009 and 2016. Trend analysis was performed to evaluate secular changes (nptrend < 0.05) in nutritional indicators and logistic regression to determine the association with individual characteristics. Results: In the study period, overweight at the beginning of pregnancy increased by 13.1 percentage points. Forty percent of pregnant women with normal initial body mass index, were overweight or obese at the end of pregnancy. The excessive weight gain decreased slightly (z=-3.33, p = 0.001), but unevenly in both cities. Adolescent pregnancy, a low education and low socio-economic level of household together with previous overweight and a family or personal history of chronic diseases are associated with excessive gestational weight gain. Conclusions: The results show social inequality. Female malnutrition by excess is a problem that must be addressed through a robust public policy, centered on primary health care level and with a focus on social determinants. Prenatal care provides a window of opportunity to intervene.