Many clinical studies have reported positive effects on babies after using recording of maternal sounds:

​​​​​

Comfort/stress/pain

• Randomized control trial:

  • “Using recorded maternal voices to limit pain in preterm infants undergoing heel lance procedures appeared safe and effective.” PMID: 28580602​, Chrico et al. 2017

  • “Auditory interventions used during heel lance reduce the pain and increase the comfort of the premature infants. White noise is extremely effective in preventing infants's pain.” PMID 32653359, Kahraman et al.2020

  • “Maternal voice and lullabies may effectively reduce pain and enhance physiological stability in preterm infants during aspiration.” PMID: 40901698, Mutlu et al. 2025

  • "Maternal voice may also induce maturation of both cognitive and respiratory control centers of the brain." PMID: 36747385, Zhang et al. 2025

  • "They indicated that a mother's heartbeat sound as a nonpharmacological and safe intervention could reduce procedural pain in neonates." PMID: 36747385, Zhang et al. 2023

• Observational study:

  • "During exposure to maternal sounds, infants had significantly lower heart rate compared to matched periods of care without exposure on the same day." PMID: 4312137​, Rand et al. 2014

  • "This study provides preliminary evidence for short-term improvements in the physiological stability of NICU infants using MSS". PMID: 22185623, Doheny et al. 2012

  • ​“Exposure to low intensity recorded maternal voice has positive effects on the preterm infants 'physiologic responses." PMID: 27914263, Sajjadian et al. 2016

  • "This study provides preliminary evidence for short-term improvements in the physiological stability of NICU infants using MSS [Maternal Sound Stimulation" PMID: 22185623, Doheny et al. 2012​​​​​

Neuro development​

​​​

• Randomized control trial:

  • ​"Increasing exposure to maternal speech via overnight audio recordings was directly linked to maturation of the left arcuate fasciculus, a white matter circuit implicated in life-long language processing." PMID: 1673471, Travis et al. 2025

• Observational study:​

  • "This study provides evidence for experience-dependent plasticity in the auditory cortex in preterm newborns exposed to authentic recordings of maternal sounds." PMC: 4364233, Webb et al. 2023

Feeding process, growth:

• Randomized control trial:

  • "Results indicated that a recorded maternal voice intervention improved preterm infants' growth and development, including weight, recumbent length, and head circumference." PMID: 36747385​, Zhang et al. 2023

  • “Preterm infants in the intervention group showed a significant increase in weight, recumbent length, and head circumference.” PMID: 37331833. Qi et al. 2023

Parents' mental health​

• Randomized control trial:

  • "The intervention of playing maternal recorded voice to preterm infants in incubators was associated with reductions in maternal depression, anxiety, and stress."​ PMID: 36747385, Zhang et al. 2023​

Several​

• Randomized control trial:​

  • ​"The combination of the auditory stimulation of the mother's heartbeat and white noise for premature infants in NICU can effectively reduce the heart rate of premature infants, stabilize their mood, promote their sleep, increase the amount of milk consumption during hospitalization, increase the rate of weight gain, and promote their physical development."​ PMID: 36747385, Zhang et al. 2023 ​​​​​​​