Does maternal heart rate variability mediate the association between postpartum depressive symptoms and preterm neonate heart rate variability (ProMote study)?

We investigated whether maternal heart rate variability (HRV) mediates the association between maternal postpartum depressive symptoms and preterm infant autonomic regulation in the early postnatal period. Data derived from 82 mothers and 97 preterm infants (gestation<37 weeks) (Mean [SD] gestational age (GA): 33.4 [2.15] weeks). We assessed preterm neonate HRV within 24 h after birth (T1), on days 3-4 (T2), and for neonates born before 35 weeks GA, at 35-36 weeks postmenstrual age (PMA) (T3). Maternal HRV measurements were carried out between the 3rd and 6th day after birth. HRV features included time-, frequency-domain, and non-linear measures. Edinburgh Postnatal Depression Scale was used to screen possible depressive symptoms in new mothers. Zero-order Pearson correlations and mediation analyses were carried out. Results: a) indicated that maternal depressive symptoms, following a preterm birth, are reliably associated with maternal autonomic regulation across all time points; b) provided limited evidence of a direct effect of depressive symptoms on preterm neonate HRV (MedianNN, T2); and c) provided evidence suggesting an indirect effect between maternal depressive symptoms and infant autonomic function via maternal HTI (T1). Maternal depressive symptoms, after a preterm birth, are associated with altered maternal autonomic regulation but do not directly or indirectly (via maternal HRV) influence infant autonomic function in early postnatal life. These findings may inform early interventions for assessing maternal HRV as a promising tool for detecting maternal mental health and highlight the role of alternative pathways linking maternal mental health to preterm infant development.