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Womb Sounds with Ocean Waves & Heartbeat

The cozy womb sound and calm heartbeat of our newborn sounds, with slow ocean waves rolling in underneath. Each wave rises and falls over about ten seconds, close to the pace of slow, relaxed breathing, so the whole sound feels like being held.

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About this sound

Womb layer	Deep, muffled whoosh, mostly below 450 Hz
Heartbeat	A calm “lub-dub” at 70 beats per minute
Waves	Muffled ocean waves that rise and fall every 10 seconds
Filter	5 kHz low-pass, soft and warm
Length	10 hours, seamless loop
Screen	Picture for a few seconds, then fades to fully black

What the research says

The womb and heartbeat layers

Before birth, babies hear mainly low sounds; the mother’s body muffles energy above about 500 Hz by 40 to 50 dB ^[1]. Very premature babies who heard their mother’s voice and heartbeat, shaped to sound like the womb, for three hours a day developed a larger auditory cortex after a month than babies who heard only hospital noise ^[2].

The ocean layer

Ocean waves are a natural broadband sound, similar to pink or brown noise. Steady broadband sound helped healthy adults fall asleep 38% faster in a sleep lab model of insomnia ^[3]. Our waves are slow and muffled, with no crashing surf or seagulls that could startle.

What we still don’t know

No study has tested womb sounds mixed with ocean waves in healthy babies at home. The research supports each layer in general, so use it as one gentle comfort alongside cuddles and a calm routine.

Why we fade to a dark screen

Young children’s body clocks are very sensitive to light in the evening. In a small study of preschoolers (ages 3–5), one hour of bright evening light cut the sleep hormone melatonin by 88%, and it stayed low for at least 50 minutes after the light was switched off ^[4]. A phone screen is far dimmer than that study’s light, and babies were not studied, but the lesson is simple: the less light in the nursery, the better. That is why every Shush Bean video shows its picture only briefly and then fades to a fully black screen.

How loud is too loud

Researchers in Toronto measured 14 infant sleep machines at full volume. At 30 cm (about 1 foot) every one of them was louder than 50 dBA, the limit recommended for hospital nurseries, and three could exceed 85 dBA ^[5]. Their advice: keep the device well away from the crib, keep the volume low, and do not run it at full volume all night. The American Academy of Pediatrics’ safe sleep guidance still comes first: baby on their back, on a firm flat surface, in their own crib or bassinet with nothing else in it ^[6].

How to use it

Lovely for the “fourth trimester”, the first three months home.
Start it during the last feed so it becomes part of the routine.
Keep the volume low and the device across the room.

Use sound gently

Keep it low. Choose the lowest volume that still masks background noise. If you have to raise your voice to talk over it, it is too loud.
Keep it far. Put the phone or speaker across the room, not in or next to the crib. Researchers who measured infant sleep machines advised keeping them more than 2 metres (about 6.5 feet) away.
Keep sleep safe. Baby on their back, in their own crib or bassinet, with nothing else in it.

Source: Hugh et al., Pediatrics (2014), as summarized by Children's Hospital of Philadelphia.

Questions

Is the heartbeat real?

No. Every layer is designed and produced by us so it stays smooth and steady for 10 hours.

Which womb sound should I choose?

Choose this one if your baby likes slow, rolling sounds. For a purer, deeper sound, try Womb Sounds for Newborns; for a shush on top, try Womb Sounds + Shush.

Are there crashing waves?

No. The waves are slow and muffled, with no loud breakers.

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
Messineo L, Taranto-Montemurro L, Sands SA, Oliveira Marques MD, Azabarzin A, Wellman DA. Broadband sound administration improves sleep onset latency in healthy subjects in a model of transient insomnia. Frontiers in Neurology. 2017;8:718. Link
Akacem LD, Wright KP, LeBourgeois MK. Sensitivity of the circadian system to evening bright light in preschool-age children. Physiological Reports. 2018;6(5):e13617. 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 page summarizes published research for general information. It is not medical advice. Research on sleep sounds for babies is still limited; talk to your pediatrician about your baby’s sleep and crying.