This paper presents reduced-form estimates of the impact of prenatal shocks on adult outcomes. The widespread fasting during the Islamic holy month of Ramadan is utilised as a natural experiment in order to estimate the impact of a relatively mild shock to individuals during gestation on socio-economic, education and health outcomes in adulthood. Previous literature shows that Ramadan observance during pregnancy is both common and detrimental to fetal health. Using the fourth-wave of the Indonesian Family Life Survey, individuals in adulthood are estimated to earn 11.4% less and have 3.8% less years of education if the month of Ramadan overlapped in full with the first trimester of gestation. The impact of the effect remains significant for the second and third trimester of gestation but declines in magnitude. Height and weight in adulthood are also found to be significantly lower for men, but this does not hold for women. The contrast in results between these biological indicators and economic outcomes suggests that there may be significant differences in compensating investment by gender. The channels of effect for the main results remains largely unknown, but there is little evidence to suggest that differing levels of physical health and/or mental cognition are the key channels of effect. Theese results suggest that the impacts of even a mild prenatal shock may be significant and persistent, but also relatively subtle in their expression.