Abstract: In this project we aim to understand how mothers’ mental health evolves after giving birth to their first child and their return to work. For identification, we exploit a Hungarian policy reform in 2014 that heavily incentivized mothers to return to work before the child’s second birthday. We find that later cohorts with the financial incentive to return earlier had better mental health trajectories; preliminary LATE estimates suggest that mothers who return to work before the child’s second birthday due to the policy have significantly lower prescription drug spending on antidepressants and tranquillizers up to the child’s sixth birthday. We investigate to what extent the better mental health trajectories may be driven by later cohorts sorting into less stressful occupations or higher-paying firms, and by different competition effects from peers.