Re-creating womb sounds perks preemies’ attention

WASHINGTON — Recordings of their mothers’ voices and heartbeats may help premature babies pay attention to speech, new research suggests.

Premature babies do better if their acoustical environment approximates what the babies would have heard in the womb, neuroscientist Amir Lahav said at a news conference February 13 at the annual meeting of the American Association for the Advancement of Science.

Typically, though, these babies spend a lot of time in hospitals’ neonatal intensive care units, places brimming with beeps, whirs and other sounds generated by life-saving equipment and people. But inside incubators, babies can be deprived of sounds, except for white noise created by the fan.

Several days after the birth of their premature babies, Lahav, of Harvard Medical School, asked 12 mothers to record themselves singing, reading and talking. Lahav and colleagues then added audio of mothers’ heartbeats to the recordings and piped the sounds into babies’ incubators for three hours a day. Toward the end of their hospital stay, babies who had heard recordings of their mothers’ voices paid more attention to a female speaker than babies who had not heard the recordings, eye-tracking and pupil-dilation measurements revealed.

Mothers’ voices and heartbeats are “part of the original recipe for how we should cook premature babies up to full maturation,” Lahav said.