Measuring spatial proximity in mother–infant interaction: A kinematic approach for an examination of the effects of maternal postpartum depression

•Maternal postpartum depression (PPD) impacts on mother–infant spatial interaction.•A kinematic approach was used to measure mother–infant spatial proximity at 4 months.•Twenty-eight dyads with mothers meeting criteria for PPD and 46 typical dyads were compared.•The PPD dyads had fewer changes in spatial proximity when compared to typical dyads.

A kinematic approach was used to measure mother–infant spatial proximity at 4 months. Maternal postpartum depression (PPD) impacts on mother–infant spatial interaction. We compared 28 dyads with mothers meeting criteria for PPD and 46 typical dyads. The PPD dyads had less variability in spatial proximity compared to typical dyads.