While this study found no associations between dietary micronutrient intakes and fetal growth, we found that lower maternal hemoglobin concentrations at 28 weeks’ gestation were associated with faster rates of fetal growth and larger placental weights and birthweights. Based on these findings we postulate the ‘consumption theory’ of pregnancy: that fetuses on faster growth trajectories have a higher requirement for oxygen that results in a greater consumption of maternal iron and hemoglobin.