Acoustic baselines of newborn vocalisations from the first minutes after birth

Objective: The crying of newborns immediately after birth has always been recognised as an expression of vitality (Moyo and Tetsiguia, 2020). Strong and rhythmic crying is associated with healthy infants, even though, there are healthy newborns who do not cry at all (Makoi and Takacs, 2012). Investigations have raised evidence that the crying of newborns may reflect the infant’s health status (Moyo and Tetsiguia, 2020), or even indicate specific pathologies, such as neurological and congenital diseases (Fort and Manfredi, 1998) or specific brain damage (LaGasse et al., 2005). However, detailed knowledge about the acoustics and temporal sequence of the first vocalisations of newborns is missing. The few existing studies mainly focused on the very first cry (Branco et al., 2005) and assessed single acoustic features, such as the fundamental frequency or (cry) duration. To fill this gap, we here aimed to provide reference values for a comprehensive set of acoustic and sequential characteristics of newborn vocalisations from the first minutes after birth.

Materials and methods: We analysed 60 audio-video recordings of vaginal births (35 female, 25 male newborns). All recordings were conducted under comparable settings in a Philippine birth centre as a gift for the parents and later on publicly distributed on the media platform YouTube. In each video, we manually segmented the respective first three minutes after birth for newborn vocalisations, which yielded a total number of 7,681 segments. Subsequently, each segment was annotated for vocalisation type. In doing so, we differentiated between expiratory and inspiratory sounds, i.e., sounds produced with an ingressive air stream. Expiratory sounds were further divided into typical crying and non-crying/other sounds. For each recording, we finally extracted the type-specific numbers of vocalisations as well as the time between birth and the respective first vocalisation; for each vocalisation, we computed the duration as well as five acoustic standard voice parameters, namely loudness, fundamental frequency, jitter, shimmer, and harmonics-to-noise ratio [1] [2] [3] [4] [5].

Results and Conclusion: We reveal the world’s first comprehensive acoustic and sequential characterisation of newborn vocalisations produced within the first three minutes of extrauterine life. We present reference values, such as a mean interval of 12s between the time of birth and the first vocalisation, a mean number of 128 vocalisations, a mean vocalisation duration of 0.53s, and a mean fundamental frequency of crying vocalisations of 369 Hz. Interestingly, we also found gender differences concerning the number of vocalisations and the fundamental frequency of crying vocalisations. This work represents an initial step towards understanding newborn vocalisation behaviour directly after birth, which is essential for any future attempt to exploit the first vocalisations of newborns as a health indicator.

Publikationsverlauf

Artikel online veröffentlicht:
19. Mai 2025

• Literatur

• 1 Branco A., Behlau M., Rehder M.I.. The neonate cry after cesarean section and vaginal delivery during the first minutes of life. International Journal of Pediatric Otorhinolaryngology 2005; 69: 681-689
• 2 Fort A., Manfredi C.. Acoustic analysis of newborn infant cry signals. Medical Engineering & Physics 1998; 20: 432-442
• 3 LaGasse L.L., Neal A.R., Lester B.M.. Assessment of infant cry: acoustic cry analysis and parental perception. Mental Retardation and Developmental Disabilities Research Reviews 2005; 11: 83-93
• 4 Makoi Z., Takacs G.. Analysis of the First Cry of the Newborns in Case of Vaginal Delivery and Caesarean Section. IFAC Proceedings 2012; 45: 478-483
• 5 Moyo G.P.K., Tetsiguia J.R.M.. Discussing the “First Cry” as an Initial Assessment for Neonates. American Journal of Pediatrics 2020; 6: 129-132