Maternal Heart Rate Variability at 3-Months Postpartum: Associations with Mental Health and Infant Neurophysiological Function

Abstract Previous research has demonstrated a critical link between maternal stress and infant development. However, there is limited understanding of how stress physiology may influence a mother’s mental state and her infant's neurophysiological functions. In the current study, we tested 79 mothers and their 3-month infants from diverse socioeconomic backgrounds. We recorded simultaneous ECG from mother-infant dyads while baseline EEG was collected from the infant. Heart rate variability (HRV) factor scores were calculated using both linear and non-linear measures, and we computed theta-beta ratio and alpha asymmetry as EEG markers for cognitive control and emotion regulation, respectively. Results first demonstrated that higher maternal heart rate variability (mHRV) was associated with lower self-reported maternal depression, anxiety, and perceived stress scores. Second, results showed positive concordance between mHRV with infant HRV scores. Finally, mHRV was not associated with differences in alpha asymmetry, but higher mHRV was associated with lower theta-beta ratios, reflecting less theta power relative to beta power. These findings suggest that mHRV may serve as a valuable physiological marker for stress regulation, influencing broader psychological states and potentially playing a role in regulating infant neurophysiology, which could result in longitudinal variations in infant self-regulation abilities.