Shush What Do Babies Hear in the Womb? Why Womb Sounds Calm Newborns
Updated 2026-11-02 · Reviewed against the sources listed below
Long before your baby arrived, they were already listening. The womb is not a silent place. It is full of low, rhythmic, muffled sounds, and that is exactly why womb sounds can feel so comforting in the first weeks after birth.
A low, muffled world
Your body acts like a natural sound filter. Low sounds, such as your heartbeat, the rush of blood flow and your voice, travel through well. High sounds are heavily muffled: energy above about 500 Hz is reduced by 40 to 50 dB before it reaches the baby [1]. So the soundtrack of the womb is deep, soft and rhythmic, never sharp or hissy.
Babies’ brains respond to these sounds
In a Harvard study of 40 babies born very early, at 25 to 32 weeks, some listened to recordings of their own mother’s voice and heartbeat, shaped to sound like the womb, for three hours a day. After a month, the hearing area of their brain (the auditory cortex) was larger than in babies who heard only normal hospital noise [2]. The researchers were careful to say that long-term effects are not yet known, and that recordings are no replacement for parents being there.
Why this matters at bedtime
There are no studies yet of womb-sound recordings for healthy, full-term babies at home. But the idea is intuitive: a deep, steady, rhythmic sound is closer to what your newborn knew for months than a silent room or a sharp, bright noise. It is one reason so many parents try womb sounds in the “fourth trimester,” the first three months after birth.
Listen: womb sounds with heartbeat and shush
A low womb whoosh, a calm 70 BPM heartbeat and a soft shush, filtered to stay muffled like the real thing. The picture fades to black after one minute.
Using womb sounds safely
Keep the volume low and the device at least 2 meters (about 7 feet) from the crib [3], and always lay your baby on their back to sleep [4].
Questions
Can babies hear in the womb?
Yes. Hearing develops during pregnancy, and babies hear muffled low-pitched sounds such as the mother’s heartbeat, digestion and voice.
Does a heartbeat sound calm babies?
Many parents find a steady heartbeat sound calming for newborns. Research in premature babies shows their brains respond to mother’s voice and heartbeat sounds, but studies in healthy full-term babies at home are still needed.
When should I stop using womb sounds?
There is no set age. Many parents switch to white, brown or rain sounds after the first few months, or keep whatever sound their baby likes.
References
- Gerhardt KJ, Abrams RM. Fetal exposures to sound and vibroacoustic stimulation. Journal of Perinatology. 2000;20(S1):S21–S30. Link
- Webb AR, Heller HT, Benson CB, Lahav A. Mother’s voice and heartbeat sounds elicit auditory plasticity in the human brain before full gestation. PNAS. 2015;112(10):3152–3157. Link
- Hugh SC, Wolter NE, Propst EJ, Gordon KA, Cushing SL, Papsin BC. Infant sleep machines and hazardous sound pressure levels. Pediatrics. 2014;133(4):677–681. Link
- Moon RY, Carlin RF, Hand I; AAP Task Force on Sudden Infant Death Syndrome. Sleep-related infant deaths: updated 2022 recommendations for reducing infant deaths in the sleep environment. Pediatrics. 2022;150(1):e2022057990. Link
This article summarizes published research for general information. It is not medical advice. Talk to your pediatrician about your baby’s sleep, feeding and crying.
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