This study evaluates how in-utero exposure to an insect pest invasion, particularly, the outbreak of desert locust swarms, affects early childhood health in Africa and Asia over the past three decades (1990-2018). Employing the difference-in-differences model, we find that children being prenatally exposed to the outbreak have their height-for-age, weight-for-height, and weight-for-age z-scores lower by 0.159, 0.148, and 0.155 standard deviations, respectively, compared to unexposed children. Our heterogeneity analyses show that the health setbacks disproportionately fall on children of disadvantaged backgrounds, i.e., those born to lower-educated mothers, poorer mothers, and rural mothers. To the extent that poor health in early life exerts long-lasting irreversible consequences over the life cycle, the study calls for effective measures to minimize the pernicious effects of the desert locust swarm outbreak