An amazing study done by Loewy J et al.  in 2013 showed that soothing music may encourage premature babies to feed better, as well as improve their vital signs (like their O2 saturation levels as well as heart rate). It is speculated that this is one of the reasons why singing lullabies to babies comes so naturally to parents and carers.
Listen to Soothing Sound and Song, a Majors for Minors album that adds soothing voices with celtic influences as well as tibetan bowls, pink noise, below average heartbeat tempos and sound frequencies, all designed to calm
 Loewy J et al. The effects of music therapy on vital signs, feeding, and sleep in premature infants. Pediatrics 2013;131(5):902-18