We provide the first causal evidence of the returns to maternal educational curricula on offspring's health at birth. Educational programs that aim to deliver more general knowledge may potentially improve women's earning potential and maternal prenatal investment by increasing the portability of skills across occupations and improving women's ability to make informed decisions about fertility options and health behavior. We study the impacts of a comprehensive educational reform that postponed students' curriculum choices and integrated more general education into the high school system on infant health outcomes. Using a dose-response difference-in-differences (DiD) model research design applied to linked population registries, we find that the reform led to a significant reduction in the incidence of very low birth weight (less than 1,500 grams) and very preterm birth (less than 33 gestation weeks). Overall, the reform's positive effects on infant health at birth seem to be driven by increased mothers' labor market opportunities and better family planning, rather than increased ability to avoid risky behaviours or increased women's earnings via different occupational choices or assortative mating. [This report received additional funding from Fundación Ramón Areces and the Spanish National Research Plan 2017-2020.]