Maternal singing during kangaroo care led to autonomic stability in preterm infants and reduced maternal anxiety

Aim: Kangaroo care (KC) and maternal singing benefit preterm infants, and we investigated whether combining these benefitted infants and mothers. Methods: A prospective randomised, within-subject, crossover, repeated-measures study design was used, with participants acting as their own controls. We evaluated the heart rate variability (HRV) of stable preterm infants receiving KC, with and without maternal singing. This included low frequency (LF), high frequency (HF) and the LF/HF ratio during baseline (10 min), singing or quiet phases (20 min) and recovery (10 min). Physiological parameters, maternal anxiety and the infants' behavioural state were measured. Results: We included 86 stable preterm infants, with a postmenstrual age of 32-36 weeks. A significant change in LF and HF, and lower LF/HF ratio, was observed during KC with maternal singing during the intervention and recovery phases, compared with just KC and baseline (all p-values <0.05). Maternal anxiety was lower during singing than just KC (p = 0.04). No differences in the infants' behavioural states or physiological parameters were found, with or without singing. Conclusion: Maternal singing during KC reduces maternal anxiety and leads to autonomic stability in stable preterm infants. This effect is not detected in behavioural state or physiological parameters commonly used to monitor preterm infants.