Postpartum depression (PPD) is associated with impairments in maternal functioning, risk of suicide and comorbidity, and negative effects on offspring development. The peripartum period is marked by dramatic neurobiological changes, yet the impact of these changes on emotional reactivity remain poorly understood. Longitudinal research examining dynamic change across this period is critically needed to chart trajectories of change and determine when women at risk for PPD can be reliably identified in order to facilitate effective timing of prevention to mitigate risk. To this end, we developed a method for measuring neural, physiological, and behavioral responses to highly salient emotional stimuli for pregnant women and new mothers (i.e., infant distress cues). We will apply this method to chart trajectories of reactivity to infant distress cues from pregnancy to postpartum with the aim of improving prediction of PPD. Participants will visit the lab at three time points (approximately 20 weeks gestation [T1], 34 weeks gestation [T2], 8 weeks postpartum [T3]). At each assessment, women will complete an infant face matching task in which they view infant emotional faces and shapes with and without interspersed infant crying audio. At the neural level, event-related potentials in response to distressed infant faces will be used to measure emotional reactivity. At the physiological level, we will examine heart rate variability in the cry vs. no-cry conditions as an indicator of adaptability to emotional demands. Women will complete a measure of depressive symptoms at each assessment, and every other week for 8 weeks after delivery.