Armed conflict has been associated with adverse pregnancy outcomes, with long-term negative health effects for current and future generations. This study analyzes birthweight in Colombia, where a long-standing conflict has created multiple stressors that may impair maternal and child health, including high levels of conflict mortality and anti-coca fumigation. We analyze births in 2000–2016 using Demographic and Health Survey data from 2004/2005, 2009/2010 and 2015/2016, which identified women's births in the last five years, combined with monthly information about local organized violence and anti-coca fumigation. Fixed effects models account for the mother's characteristics and pregnancy-related factors. We assess both main effects and heterogeneous effects according to the mother's level of education, exposure during different trimesters and at two levels of spatial aggregation, as well as the compounding risks of being exposed to both violence and fumigation. Our study shows that local exposure to organized violence during pregnancy is detrimental to intrauterine growth, resulting in lower birthweight. More localized exposure to fumigation was not significantly related to birthweight, potentially due to the low share of sampled women being exposed and selection into live birth. However, exposure measured at more aggregated levels significantly predicted reduced intrauterine growth. These within-family effects are particularly strong among less educated mothers. Further, our findings suggest compounding risks of exposure to both hazards. The findings indicate a scarring effect from armed conflict on newborns that may impair their future health and socioeconomic status outcomes. The results highlight the critical role that context plays in shaping individual health outcomes and the importance of intersectional approaches in future research and interventions.