The main hypothesis to explain fetal growth restriction (FGR) is placental insufficiency. Yet, whether the maternal socioeconomic status has an influence on fetal growth has not been fully elucidated. We sought to assess ecogeographic differences in the distribution of FGR in a city and to assess whether the pattern is influenced by socioeconomic status. This population-based, ecological study involved data from 8675 deliveries between 24 and 42 weeks in three obstetric centres from Cartagena in northern Colombia during 2017-2018. Infants were classified as SGA according to INTERGROWTH-21 standards. Maternal socioeconomic status was assigned according to affiliation to the health care system and the residential area within the city. Frequency variability of SGA neonates among city geographic areas and the influence of maternal socioeconomic status were calculated. The frequency of SGA was 8.1%. The rate of SGA per neighborhood was significantly higher in the lower-income than in the higher-income socioeconomic areas [5-11% (810/7369) vs 1-5% (65/1306); p < 0.05]. Similarly, the median birthweight centile was significantly lower in low-income compared to higher-income neighborhoods on the city map. Supporting information can be found in the online version of this abstract Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.