Yang N, et al. – Purpose of this investigation was to study the correlates of early pregnancy serum brain–derived neurotrophic factor (BDNF) concentrations. The findings suggested that maternal age, early pregnancy body mass index (BMI), gestational age, and the presence of moderate antepartum depressive symptoms were statistically significantly correlated with early pregnancy serum BDNF concentrations in low–income Peruvian women. In addition, biological changes of C–reactive protein (CRP) during pregnancy might affect serum BDNF concentrations.