In this literature review I’m going to present relevant sources about the use and effect of music therapy in preterm newborns. Neonatology has undergone profound changes in recent decades, which provided significant improvements in care for premature newborns and their families (Santos, Pereira, Santos & Santana, 2012). The survival of preterm babies has increased, enabling neonates with extreme gestational ages and/or of very low birth weight to survive (Silva, Cação, Silva, Marques, & Merey, 2013). Preterm has psychological and anatomical features that emphasize the baby’s systemic frailty, as the immaturity of the respiratory and central nervous system. The fragility conditions, such as extreme prematurity, low birth weight, and perinatal conditions, can lead the newborn to require long periods of hospitalization, promoting early separation between mother and child. This may be associated, in the long-term, to disturbances of affectivity, limited abstract thinking, and cognitive difficulties (Silva et al., 2013). The preterm babies in Neonatal Intensive Care Units (NICU) are often exposed to continuous noise, which can interfere with development, since excessive auditory stimulation creates negative physiological responses, such as apneas and fluctuations in heart rate, blood pressure and oxygen saturation, besides making patients more vulnerable to hearing loss, abnormal sensory development, and speech and language problems (Brown, 2009). In their research, Trevarthen and Aitken (2001), provide evidence that infants are selectively attracted to the emotional narratives carried in the human voice, and that they are excited to participate in a shared performance that respects a common pulse, phrasing, and expressive development. Infants respond with synchronous rhythmic patterns of vocalizations, body movements, and gestures to match or complement the musical/poetic feelings expressed by the mother. As infants become more energetic and alert, mothers’ songs and games become more lively. They develop ritual forms which are often repeated, to the great satisfaction of infant and parent. The mood of the mother’s performance changes with the state of alertness and humor of the baby, and reacts with a soothing, calming mode when the infant is tired or distressed. The songs can modulate the emotional state of the infant and the extent to which he or she engages in communication. By six months of age, in laboratory discrimination tests, infants respond differently to play songs and lullabies, types of song that are easily recognized by adults. Play songs are associated with increased alertness to the external world and joint attention, whereas lullabies result in more self-focused infant behaviors (Rock, Trainor, & Addison, 1999). Regarding music therapy, the use of music as a complementary tool for health promotion has been recently reported in the medical literature. Defined as the therapeutic use of music or musical activities in the treatment of mental and somatic diseases, music therapy has accumulated scientific evidence of its effectiveness in pain management, anxiety and emotional stress, among other conditions (Lai, Chen, Peng, Chang, Hsieh, Huang, & Chang, 2006; Keith, Russell, & Weaver, 2009; Klassen, Liang, Tjosvold, Klassen, & Hartling, 2008; Hatem, Lira, & Mattos, 2006). Trevarthen and Aitken, also indicate that there clearly is a sensitive two-way mirroring of the emotional values of expression in spite of the great difference in maturity between the participants. This talk is understandable as effective communication only if it is accepted that even young infants are as sensitive to the feelings behind consciously regulated well-motivated utterances as an old person or a cat. Another article, of Standley (2002), had the purpose to conduct meta-analysis on the effects of music with premature infants and to determine if sufficient evidence exists to include music therapy in the clinical protocols of the neonatal intensive care units (NICU). Results demonstrate that music therapy procedures provide significant benefits to premature infants that are consistent across the following diverse variables: the adjusted gestational age of the infant at the time of music intervention; the decibel level of the music within a range of 55 to 80 dB; the mode of delivery (free field/earphones); and the birthweight of the infant. Additionally, results are consistent across all variables measured: observed behavioral state, heart rate, respiration rate, oxygen saturation level, weight gain, days in hospital, feeding rate, and nonnutritive sucking rate. Similar studies have shown multiple benefits from short periods of continuously playing music in the incubator. Infants remain calmer and demonstrate more stable physiologic measures (Lorch, Lorch, Diefendorf, & Earl, 1994), have higher oxygen saturation levels (Cassidy & Standley, 1995; Collins & Kuck, 1991; Standley & Moore, 1995), gain weight faster (Malloy, 1979), and require a shorter time to reach discharge criteria (Caine, 1991). Additionally, the infants in Caine’s study were rated by their mothers to be calmer than those without music intervention at 6 months’ post discharge follow-up (Standley, 1991). The very recent (2016) meta-analysis, by Bieleninik, Ghetti, and Gold, showed significant positive effects of music therapy on the clinically important outcomes of respiratory rate and maternal anxiety. Narrative synthesis of less common outcomes also suggested some benefits of music therapy during and immediately after NICU hospitalization. Music therapy reduced infants’ respiratory rate by 3.91 breaths per minute. These findings suggest that music therapy lowers stress and contributes to clinical stability. The significant positive, short-term effect of music therapy on maternal anxiety was large according to Cohen’s (1988) guidelines for interpreting effect sizes. The observed reduction in mean anxiety scores also corresponded to a shift from clinical to subclinical levels of anxiety (Julian, 2011) in two of the three included studies (Arnon, Diamant, Bauer, Regev, Sirota, & Litmanovitz, 2014; Schlez, Litmanovitz, Bauer, Dolfin, Regev, & Arnon, 2011). Elevated maternal anxiety is associated with postpartum depression and impaired parenting in mothers of preterm infants, whereas reduction in maternal anxiety is associated with improvements in child development during the first two years of life (Benzies, Magill-Evans, Hayden, & Ballantyne, 2013). The three studies included in the meta analysis of maternal anxiety all used live music in conjunction with ‘kangaroo’ care, demonstrating greater improvements than with ‘kangaroo’ care alone. The 3-day reduction in length of hospitalization in the above meta-analysis failed to reach statistical significance, but if confirmed in a larger study, would have important implications for service costs. The results of another research about the effect of music therapy on preterm infants (Malloch et. al., 2012), support the proposition that a music therapy intervention can facilitate the neurobehavioral development of the medically fragile newborn infant in the often socially unsympathetic, non-contingent context of the NICU. The overall pre-intervention Neurobehavioral Assessment of the Preterm Infant (NAPI: Korner & Thom, 1990) scores for the two NICU groups showed no significant difference, but post-intervention, the group receiving music therapy obtained a significantly higher score. Moreover, the effect size observed in overall NAPI score from pre- to post-intervention was large for the NICU music therapy group, but small for the NICU-no- music therapy group. This results suggests that the infants who receive the music therapy intervention are better able to maintain self-regulation during social interaction with an adult: They are less irritable, cry less, and are more positive in their response to adult handling. In other words, they protest less when an adult interacts with them. The writers suggest it may be that through the music therapy intervention the infants became less negatively reactive to adult contact, which up until the intervention may have been often painful, non-contingent, and nonsocial. Furthermore, the NAPI measures in which were found group differences were of infant regulation. That is, the music therapy infants were abler to cope with a standardized series of handling and orientation items without becoming physiologically or psychologically dysregulated (e.g., autonomic nervous system changes, irritability). Hatem et. al. (2006) assessed the behavior of heart rate in children undergoing sessions of music therapy in the postoperative period of cardiac surgery and found that the reduction of this variable may be related to reduced anxiety of patients hospitalized in NICU. Arnon et. al. (2006) observed that the therapy with live music in the NICU was associated to a significant decrease in heart rate, leading to a calmer and deeper sleep of newborns 30 minutes after the end of the session, in addition to improvements in the respiratory rate and O2 saturation. Cevasco (28) evaluated the behavior of preterm and term infants exposed to music therapy during 20 minutes for 3 to 5 days in two consecutive weeks, comparing them to a group of newborns not exposed to music, and observed a shorter hospitalization time in the Experimental Group. Lubetzky et. al. (2010) assessed 20 healthy preterm newborns in order to test the hypothesis that the “Mozart effect” reduces the resting energy in growing patients, and observed that those submitted to sessions of 30 minutes of music therapy twice a day presented reduction of energy expenditure compared to the group that was not exposed to music therapy. In the Silva et. al. (2013) study they did not observe an immediate effect of music therapy on the variables systolic blood pressure, diastolic blood pressure, and body temperature in the six sessions performed. According to the writers, a generalization of the results obtained in this study is disadvantaged by sample size and the heterogeneity of the sample, such as chronological age, birth weight, previous medications, clinical complications, use of endotracheal tube, as well as lack of calculation of sample power. To sum up, when approaching this field, of music therapy in preterm newborns there are many important factors to consider. First, one of the major limitations of most studies is the lack of long-term observations. We can’t really know if the influence we see, or want to see is significant in the long-term, even if in some cases it is significant in the short-term. There was a strong tendency toward facilitating parental involvement in music therapy. This also, facilitates mutually beneficial interactions that support infant development, help parents assume a primary caregiving role, and foster healthy bonding during the critical period of NICU hospitalization. A variety of research studies with a larger subject pool is necessary to clarify the efficacy of specific procedures for music exposure, especially regarding prime gestational age, length of exposure, and decibel levels. Additionally, a larger pool of studies would allow for analysis for a particular dependent variable. Lastly, studies with multiple intervention opportunities, evaluating different kinds of music therapies and more carefully controlled subject groupings would seem necessary.