Effects of infant fear on changes in infant heart rate variability after maternal postpartum depression treatment.

This study examines how infant temperament, particularly fear, influences physiological improvements in infants following maternal postpartum depression (PPD) treatment. Forty infants of birthing parents with major depressive disorder and 40 healthy controls were recruited. Parents with PPD participated in a nine-week cognitive-behavioral therapy intervention. Infant emotion regulation was assessed using high-frequency heart-rate variability (HF-HRV) and frontal alpha asymmetry (FAA) at baseline (T1), immediately post-treatment (T2), and three months later (T3). Birthing parents also reported on their infant's temperamental fear using the Infant Behavior Questionnaire-Revised Short-Form at these times. A significant increase in HF-HRV was observed immediately after treatment in the PPD group which persisted at T3. While no Group × Visit × Fear interaction emerged from repeated measure models, follow-up regression analyses within the PPD group revealed that higher baseline fear was associated with smaller increases in HF-HRV from T1 to T2 or T3. Although FAA shifted leftward over time, fear did not significantly predict FAA changes. No associations between fear and physiology were observed in the control group. The study suggests that infant fear may reduce the physiological benefits of maternal PPD treatment for infants, underscoring the importance of considering infant characteristics when assessing the impact of maternal PPD interventions.