From a study by Amagdei A, Balteş FR, Avram J, and Miu AC:
Several studies have indicated that the exposure of rodents to music modulates brain development and neuroplasticity, by mechanisms that involve facilitated hippocampal neurogenesis, neurotrophin synthesis and glutamatergic signaling. This study focused on the potential protection that the perinatal exposure to music, between postnatal days 2 and 32, could offer against functional deficits induced by neonatal callosotomy in rats. The spontaneous alternation and marble-burying behaviors were longitudinally measured in callosotomized and control rats that had been exposed to music or not. The results indicated that the neonatal callosotomy-induced spontaneous alternation deficits that became apparent only after postnatal day 45, about the time when the rat corpus callosum reaches its maximal levels of myelination. The perinatal exposure to music efficiently protected the spontaneous alternation performance against the deficits induced by callosotomy. The present findings may offer important insights into music-induced neuroplasticity, relevant to brain development and neurorehabilitation [emphasis added].
Here we see that exposure to music during birth affects the ability of the brain to protect the brain against injury. Although it’s questionable to generalize between species, rat brains and human brains work in much the same way, which is why we experiment on rats first. Therefore, having classical music playing in the waiting and delivery rooms seems to be a “no-brainer” (sorry for the bad pun, it’s that kind of day).